@DarkPhoenix #73909
I’ll give him one thing, that there are two physical sexes, and they are encoded in our DNA. But unfortunately for his argument, DNA also doesn’t work the way he thinks it does.
For one, a simple explanation from someone without advanced biological study: The XX/XY chromosomes often used to determine sex genetically, actually do not determine physical sex. Instead, at least one gene (or set of genes) actually determines the fetus’s response to an androgen bath in the womb. Should the fetus absorb them (according to the status of the gene(s)), the sexual characteristics will develop as typically male, forming a penis and testicles most notably. If, on the other hand, the fetus is insensitive, the androgenic hormones will not be absorb and utilized, and the fetus will instead develop a vagina and ovaries.
Even the four scenarios established by this (XX:vagina, XY:penis, XX:penis, XY:vagina) all still assume though that genetic encoding and decoding all work perfectly. They don’t. And this is why we get intersex people, with partially formed genitalia for both sexes. As well as a number of other less common variants.
And even all of that has nothing to do with how people respond to their genitalia and their own gender identity, but frankly that’s a whole other mess that even people who agree on it never really agree, as they’ll always find out when all the details are laid out.