Human Sexes, Gender and Transgender

 At the present time - 2022 - there is much in the media about the issues of gender and sex. These are also topics that generate a lot of (sometimes heated) discussion. So this post aims to clarify some of this area.

Sex (Definition): Either of the two major forms of individuals that occur in many species and that are distinguished respectively as female or male especially on the basis of their reproductive organs and structures. (Merriam-Webster Dictionary)

Sexual Orientation (Definition): An enduring pattern of romantic or sexual attraction (or a combination of these) to persons of the opposite sex or gender (heterosexual), the same sex or gender (homosexual), or to both sexes and more than one gender (bisexual). The lack of sexual attraction to others (asexuality) is sometimes defined as a fourth category. (Wikipedia)

Sex: Your birth certificate is the document that records the sex (male or female) of a child born in the UK. This information is given to the local Registrar by the person registering the birth, usually one of the parents, along with the forenames that have been chosen for the child. 

For the vast majority of births, the physical sex of the child is obvious as either male or female. For a very rare number, the sex of the child is indeterminate or where there are intersex traits. It is estimated that this occurs once in every 1,500 births, In these cases the General Register Office advice is that registration is deferred until medical investigations are complete. 

Tests typically include testing chromosomes, hormones and internal organs. Test results do not always indicate male or female, but can be on a sliding scale between the two. Ultimately the sex chosen for an intersex baby is the one doctors and their family believe they will grow up to identify with best. In past years, surgery was typically the first thing to do, but many now feel this should be delayed. 

To further complicate matters, some Disorders of Sex Development (DSD) are not obvious from external appearance and are only identified later when a child needs surgery (e.g. for a hernia) or hormone testing for other reasons. 

Sexual orientation: It is only possible to estimate the proportions of a population that identify as lesbian, gay or bisexual by using the statistics from national surveys and censuses. In the UK in 2019, an estimated 1.4 million people aged 16 or over identified as LGB; this was around 2.7% of a population of c. 67.1 million.

There are differences in age groups. While 2.7% of those aged 16 and over identify as LGB, the proportion of all 16 to 24 year old's identifying as LGB is around  6.6%. Possible reasons for this pattern are that younger people could be more likely to explore their sexuality, combined with more social acceptance of different sexual identities and the expression of these today. However, for the first time, older people (aged 65 years and over) also showed an increase in those identifying as LGB (from 0.7% in 2018 up to 1.0% in 2019).

Source: UK Office for National Statistics. NB: Since these figures have not been collected in the past, it is not clear what proportion of those aged 16-24 will continue to identify as LGB as they progress through adolescence.)  

Gender (Definition): Gender is the range of characteristics pertaining to femininity and masculinity and differentiating between them. Depending on the context, this may include sex-based social structures and gender identity. Most cultures use a gender binary, having two genders; those who exist outside these groups may fall under the umbrella term 'non-binary'. (Wikipedia)

Transgender (Definition): Transgender people have a gender identity or expression that differs from the sex they were assigned at birth. The term may also be used to refer to people who are non-binary or genderqueer, and to cross-dressers. Being transgender is distinct from sexual orientation. (Wikipedia) Some transgender people undergo surgery hormone treatment and lifelong hormone treatment to 'become' the other gender. However, genetically their body cells will remain female or male, which may have other health implications.

Transsexual (Definition): People who desire medical assistance (hormone treatment and surgery) to transition to the physical characteristics of another sex. (Wikipedia)

Human Biology

Genetics and DNA have revealed that humans are not just born male and female. There are at least six biological sexes that can result in fairly normal lifespans. (In addition there are other 'sexes' that result in spontaneous abortion as the body identifies the foetus as non-viable.)

Even today, people think of someone as a 'man' if they look masculine and as a 'woman' if they look feminine. This can lead to some significant misunderstandings of how the world actually works.

• Mokgadi Caster Semenya: An intersex woman, assigned female at birth and has always lived as a woman, with XY chromosomes and naturally elevated testosterone levels. However as a runner, other competitors felt her higher testosterone levels gave her an unfair advantage over XX women. 2018: The international athletics federation, announced new rules to apply only to those with the 46,XY karyotype, who are now required to lower their testosterone levels in order to compete in the female classification. The medication taken can have side effects.
• Transgender male to female competing in women's events. More and more male-to-female athletes are competing in women's competitions, creating a dilemma for all involved. Such athletes have been allowed to compete in women's Olympic events since 2012 on condition that this is after castration and two years of hormone therapy. However, others feel that they still have an advantage of the benefit of more androgen for their first 20 years of growth, with a male type skeleton and musculature. It is also likely that a male athlete will have a male brain, since developing foetuses have male imprinting of the brain, which does not go away after androgen  supression and sex change surgery.

The sex of a baby is determined by its sex chromosomes, with XX being female and XY male, but is typically identified by its genitalia or visible sex organs (penis and vagina). However, some babies with the genetic variants listed below can appear to be females or males but actually have other sex chromosome combinations. A study in Great Britain showed that 97 out of 100 people who were actually XXY thought they were a normal XY male, and had few signs that this was not the case.

• XX = Most common form of Female
• XY  = Most common form of Male
• X  = Turner's syndrome (roughly 1 in 2,000 to 1 in 5,000 births). This chromosome variation happens randomly when the baby is conceived. It is not linked to the mother's age. These females tend to be shorter than average, and have under-developed ovaries. Most likely to be diagnosed between the ages of 8 to 14.
• XXY = Kleinfelter syndrome (roughly 1 in 500 or 1 in 1,000 births). Males are born with an extra X chromosome. Many of them are unaware they have the extra chromosome. Infertility tends to be the main problem.
• XYY = Jacob's syndrome (roughly 1 in 1,000 births). Affected individuals are usually very tall. Many experience severe acne during adolescence, and other symptoms may include learning disabilities and behavioural problems such as impulsivity.
• XXXY = (roughly 1 in 18,000 to 1 in 50,000 births). Characterized by the presence of 2 extra X chomosomes in males. Sometimes referred to as a variant of Klinefelter syndrome, but differs from that and is more severe. Signs and symptoms vary but include learning difficulties, intellectual disability, low muscle tone, delayed growth, distinctive facial features and various birth defects that may affect the genital and musculoskeletal systems. Many have poorly developed social skills and delayed language development. The condition is not inherited and likely results from a random error in cell division.

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UK Population 2022

Respondents to a recent YouGov survey of 1,800 adults indicates that people overestimate the scale of ethnic, religious and sexual minorities in the UK and underestimate the white population. So what are the official figures?

Religion: Some 4% are Muslim, and just 0.5% are Jewish.

Ethnicity: 87% are White, 3% are Black, and 10% other ethnicity.

Diet: Around 4% are Vegetarian.

Sexual orientation: Some 1.3% are Bisexual, and 1.8% are Gay/Lesbian. Between 0.3% and 0.7% self identify as a different gender to their biological sex.

Why does the public view differ from the actual figures? Recent efforts to be more inclusive in films, the music industry, broadcasting (tv) and print media, and to remove historical bias against minorities in applying for jobs, and being the first to lose jobs (e.g. in downsizing companies), together with the fact that ethnic minorities tend to live close by others of like ethnicity, have inadvertently skewed public perception.

I've not been able to find the YouGov survey results so no link to that.

Source: Mick Hume article in Daily Mail, 7 June 2022

Eurovision Voting Explained

Confused by the voting for the 2022 Eurovision song contest? I was too, so I've checked out what exactly goes on.

There are two sets of votes. These are (a) the votes of the national juries and (b) the public telephone vote.

Voting by national juries.
The juries watch the second dress rehearsal and rank all the entries in order in a single list. The entry that is top of the list gets 12 points, the second on the list gets 10 points and the third on the list gets 8 points. The entries from fourth down are allocated 7, 6, 5, 4, 3, 2 and 1 points.

These results are announced live at the event by video from each country.

Voting by public
Voting takes place during a specific timed slot after the jury votes are announced. Members of the public vote by telephone. The number of votes for each entry are counted and the entries are then ranked in order from most popular to least popular. The points allocated are the same as for the juries: 12, 10, 8, then 7 down to 1. The points from all participating countries are combined into a single score, so with 40 participating countries, the maximum number of points available is 480 (40 x 12).

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Mutations and the risk of cancer

 A new study carried out by the the Wellcome Trust Sanger Institute sheds new light on the role of genetic changes in ageing and cancer. By comparing the accumulation of mutations across many animal species, researchers found that despite a huge variation in lifespan and size, different animal species end their natural life with similar numbers of genetic changes.

The study (published 13 April 2022 in Nature) analysed genomes from 16 species of mammal, from mice to giraffes. The analyses confirmed that the longer the lifespan of a species, the slower the rate at which mutations occur, lending support to the theory that somatic mutations play a role in ageing.

Somatic mutations are genetic changes that occur in all cells throughout the life of an organism. In this natural process, in humans cells acquire around 20 to 50 mutations per year. Most of these are harmless, but some can start the process of developing cancer or impairing the normal functioning of a cell. 

Since the 1950s there has been speculation that these mutations may play a role in ageing, but it is only now with technology able to observe genetic changes in normal tissue that research can start to answer whether this is the case.

Peto's paradox. Since cancers develop from single cells, species with larger bodies (and therefore more cells) were thought to have a higher risk of cancer. But cancer incidence across animal species is independent of body size. Large bodied animal species are thought to have evolved mechanisms to prevent cancer but until now this has not been tested.

The Wellcome Sanger Institute study used new methods to measure somatic mutation in 16 mammalian species with a wide range of lifespans and body sizes, including human, mouse, lion, giraffe, tiger and the long-lived and highly cancer resistant naked mole-rat. Mutation rates were measured in intestinal stem cells. Analysis of the patterns of mutations indicated that somatic mutations accumulated linearly over time, and were caused by similar mechanisms across all species, including humans, despite different diets and life histories. Also the rate of somatic mutation decreased as the lifespan of each species increased. Researchers now want to study further diverse species, including insects and plants.

Peto's paradox still needs an answer, since after accounting for lifespan, researchers found no significant link between somatic mutation rate and body mass, indicating that other factors must be involved as well. It does not seem that evolution has chosen a single way of controlling the incidence of cancer, but that it is possible that every time a species evolves a larger size than its ancestors, evolution might use a different solution to the problem.

On average a giraffe is 40,000 times bigger than a mouse, and a human lives 30 times longer, but the difference in the number of somatic mutations per cell at the end of lifespan between the three species only varied by around a factor of three.

The exact causes of ageing remain unsolved, though it is likely to be caused by the accumulation of multiple types of damage to cells and tissues throughout life, including somatic mutations, protein aggregation and epigenetic changes.

Source: Mutations across animal kingdom shed new light on ageing in Science Daily, 13th April 2022.

What Time of Day to Take Vitamins

 Nearly half the UK population take vitamin supplements, but experts say when and how you take them changes how effective they are.

Iron: Around three-quarters of women are at risk of iron-deficiency anaemia, mainly due to iron loss during their monthly periods.

• Take on an empty stomach an hour before bed (and two hours after supper) and combine it with vitamin C or A.
• Vitamin C can help your body absorb iron as it bonds to iron particles, helping them to dissolve more completely in the gut. Vitamin A can also improve iron absorption.
• Look for iron supplements that contain vitamin A, or its precursor beta-carotene.
• Take iron supplements on alternate days, as a 2017 study found that more iron is absorbed taken this way.
• Avoid taking with dairy, tea or zinc pills. Certain foods, especially dairy - including milk-based drinks, can block iron absorption. And since tea sipped with a meal can inhibit the absorption of iron by up to 90%, take your iron pill with water. And zinc competes with iron because both minerals need to attach to the same 'transporter molecules' in the gut.

Calcium: Many menopausal women take calcium to help prevent the bone-thinning disease osteoporosis. Calcium is often combined in a pill with magnesium, which is also good for bones.

• Take a supplement (ideally also containing magnesium, vitamin D and vitamin K) with food.
•  Taking calcium with food will also enhance absorption. Look for products with calcium citrate, which is better absorbed than calcium carbonate.
• Avoid taking with zinc or iron pills.

Vitamin D: In the winter months, around half the UK population is low in vitamin D, a nutrient vital for healthy bones and strong immunity. This is because we make vitamin D via sun exposure on our skin.

• Take 10mcg during the winter, in the evening with food (or largest meal of the day) containing fat.
• Vitamin D is better absorbed if taken with a meal that contains some fat, such as avocado, egg yolks or olive oil.
• Avoid taking with vitamin E pills; as both are absorbed in the same way.

Vitamin C: Important for the immune system and vital for healthy skin and bones. It is a water soluble nutrient that we can absorb in doses of up to 400 mg. Any excess above this is not stored by the body, but passed out in urine.

• Take in the morning on an empty stomach. 
• If taking doses larger than 400 mg (e.g. during a cold), split these throughout the day. 
• A standard supplement will give you more than enough vitamin C so no need to take liposome-encapsulated products.
• Best absorbed on a completely empty stomach, e.g. before breakfast, as absorption can be hindered by proteins and fibre in food.

Fish oil: A rich source of two omega-3 fats (EPA and DHA) that have proven benefits for a wide range of illnesses including low mood, heart disease and rheumatoid arthritis.

• Take with food that contains fat, which triggers the pancreas to release enzymes that help break down the omega-3 oils into fragments small enough to be absorbed through the gut wall.
• Avoid taking before a workout or sleep to avoid unpleasant fishy burps.

B vitamins: The group of eight B vitamins (including B6, B9 (folic acid), and B12 are vital for healthy blood, nerve function and energy levels. They are water-soluble.

• Take first thing in the morning on an empty stomach. Choose a supplement with a blend of different B vitamins.
• Take a blend of B vitamins. Taking folic acid alone can trigger or mask a deficiency in vitamin B12.
• Avoid taking last thing at night as high vitamin B6 doses can interfere with sleep. Avoid taking with food, as vitamin B12, in particular, binds to the food we eat and can then end up passing straight out of the gut as waste without being absorbed.

Probiotics: These are 'good bacteria' that make up part of our gut microbiome - the community of bacteria that plays a vital role in our digestive health and immune system. A poor diet or medication such as antibiotics can kill off good bacteria, helping bad ones to survive, increasing the risk of gut infections or digestion problems. Probiotic supplements aim to replenish levels of good bacteria. As they are live bacteria, they need to reach the gut intact.

• Take: half an hour before eating. Take before a meal containing some fat. 
• Avoid: taking with hot drinks, juices or alcohol.

Magnesium: Useful for bone health. 

• Take: if using alone for a relaxing effect, take at bedtime.
• Take care: If you take calcium, then magnesium may help ease anxiety, restless legs, muscle cramps, migraine and improve overall sleep. You should take roughly twice as much calcium as magnesium.

How to take supplements

• Swallow with a big glass of water. Fluid intake is important to dissolve the tablet, especially for water-soluble nutrients such as B vitamins and vitamin C.
• Avoid coffee, tea and energy drinks (these also contain caffeine) as caffeine can interfere with the absorption of nutrients. And it's best to wait for an hour after drinking coffee to take supplements.
• Taking a multivitamin could be a waste of money, as some of the nutrients can compete for absorption. And as they contain both water-soluble and fat-soluble vitamins, taking them on an empty stomach means you don't absorb much of the fat-soluble ones, while taking them with a meal may impair absorption of water-soluble ones.
• Don't eat nuts before taking minerals (e.g. iron, calcium and magnesium). Phytic acid found in nuts, beans and bran binds to minerals in the gut, meaning that they won't be properly absorbed. This only affects absorption of nutrients eaten at the same meal.

Source: Are you taking your vitamins the right way - or just wasting your money? Experts say that when you take them can determine how effective they are by Caroline Jones, Daily Mail, 28 Feb. 2022