Unless I am hearing it from a doctor, the vast majority of the time the argument is brought up, it is by men or women trying to defend the old way of doing things. For guys, it's usually in business and career. For girls, it's usually in dating. Because it has to do with who had advantage/disadvantage in each situation.

I have used the argument myself. Generally in defending the idea that, given total agency, equality, and freedom, people will still make different career choices that have different pay and life balances, and trying to eliminate those differences is tantamount to erasure. That is still, in essence, defending an "old way" of sorts.

We can’t ignore the fact that biologically, men and women are different, but we can ignore arguments that link such biological differences to social differences between men and women.

• One biological difference is our sex chromosomes. Men typically have an XY chromosomal pattern, whereas women tend to have an XX chromosome pattern. This is a difference at the biological level.
• Another difference is in reference to reproductive hormones. These are produced in our reproductive organs. These are the testes for males and the ovaries in females. Typical reproductive hormones for females are oestrogen and progesterone. The typical reproductive hormone in males is testosterone, FSH and LH.
• Usually and typical are used here in that sometimes men and women are born with mixed reproductive organs, as such are born intersex. Some medical conditions like PCOS for example also cause increased levels of testosterone in women.
• I don’t think it is a useful contribution to the discussion to deny there are biological differences between males and females. This is obviously not the case. We should focus more on debunking the idea that it is such biological differences that mean men and women are different in more social aspects. They in no way shape how men and women can function and contribute to society.
• For example, it is often argued that testosterone means men are biologically stronger thus more suited to labour roles. This is not the case. It is when we use biological differences to justify this line of reasoning that there becomes an issue.