Because this feels like a loaded statement, I'd respond like this: Biology makes mistakes. Biology is fallible. To frame this about biology is not sufficiently complex to address the issue.
- Talk to experts.
- The initial statement seems to me is that of a culture warrior, not a curious mind. Therefore it doesn't matter to me.
- Compassion doesn't require logic. But if you want sonething slightly logical: I don't understand quantum physics either. I'm reliably informed it exists. Me being unable to grasp the uncertainty principle leaves me feeling uneasy and frustrated. Others may feel in a comparable way about gender identity. It's okay to admit that you don't get it. I don't fully understand it either. It's not okay to be an asshole about it.
- Apples to rotten pears.