I endorse this article: 5 Ways That Science Supports Feminism – Not Gender Essentialism. It’s making the point that when you actually study the relevant sciences, you discover that they fundamentally support a more complex view of sexuality than the usual boy/girl dichotomy. Here, in brief, are the five points it makes:
1. There Are More Than Two Sexes, Not to Mention a Vast Range of Gender Identities
2. The Environment Impacts Human Development from the Very Beginning at the Cellular Level
3. Socialization Is a Powerful Force
4. When Studies Do Find Gender Differences, They Are Often Too Weak to Serve as the Basis for Generalizations
5. Gender Means Different Things in Different Cultures
One other factor that leads people to adopt gender essentialism is a kind of innumeracy — I swear, I think the only statistical measure most people understand is the mean. But statistics was developed to describe variation, in addition to taking data sets and crunching them down to a single number.
There is also deficiency of logic. If you take any diverse set, divide it in two, and calculate the mean of any given parameter for both, you’ll get…two numbers. This does not validate your initial division as appropriate. It does not mean your artificial dichotomy reveals an absolute truth about the world. It does not mean you have encapsulated the essence of your two groups in a single simple metric. In particular, it’s possible to have a mean that does not describe a single individual in your group accurately.