All science & statistics resources
The biology of the human body
There is much debate about how society changes, and how the law must reform to keep up. However, human biology has not changed. The sex of a baby is determined at the moment of conception, and can be identified in utero. Being male or female is coded in our DNA and in every cell of our bodies. We are generally very good at recognising who is male and who is female. Pathologists and archaeologists can determine the sex of a body from its bones. Some activists talk about a sex spectrum, but this is nonsense. Some human characteristics are on a spectrum – height and weight, for example. Others such as hair, eye and skin colour have a range of possibilities. Sex is a simple binary. All humans are born of a female, having been made from a small gamete (sperm) from a male which fertilises a large gamete (egg) in a female.
It may seem surprising that this needs to be said. Trans activists like to suggest that sex is not a simple binary. They refer to “sex assigned at birth”, as if it’s an arbitrary decision, or based on guesswork. The fact is that a baby’s sex is observed at birth by looking at its genitals, which are its secondary sex organs. (Internal sex organs involved in reproduction are the primary sex organs). This is true for 99.98% of babies. A tiny percentage of babies are born with a disorder of sex development (DSD), also known as intersex which makes their secondary genitals abnormal, and hence at birth their sex is hard to read. Nowadays, this can be resolved with a simple chromosome test. Most babies with a DSD or intersex condition are obviously male or female at birth. Read more about chromosomes, biological sex and gender, and DSDs, here.
Male and female bodies are very different. This matters, especially in sport. Biological sex differences are explained here. A recent book by Caroline Criado-Perez, Invisible Women, documents some of the ways society has failed to take proper account of these differences, for example in product design and in healthcare.
Studies of the transgender population
Fair Play For Women has compiled several studies to help people to understand the UK transgender population by age and sex. Because they are often presented as a particularly oppressed group, we have also researched their status both as victims and as perpetrators of crime, and compared this with the general population. You may be surprised to know that male-to-female transitioners (“transwomen”) are less at risk of violence than women. As a group their offending rates are much the same as those of men, though worse in sex offending and violent crimes. This means that while not every trans person presents a risk, as a group they are no less risky to women than men are. In our society, men are expected to stay out of women-only spaces, despite the fact that most men are not offenders, because some are. Our research indicates that the same is true of transwomen. The much-cited suicide risk among transgender youth, used to suggest they are a particularly vulnerable group whose needs must be prioritised, is also unreliable, as we show here.