All of these are cultural.

Laws are cultural.

You have explicitly stated you do not want to discriminate by gender, age or race, but that is exactly what will happen with mental capacity tests.

Muddying the definition of "discriminate".

He wants to apply the same standard to every single individual. Non-discriminatory. Simple.

On the other hand, the very purpose of such a test is to discriminate between those who are informed to give consent, and those who aren't.

If a person can display an adequate understanding of what relationships and sex mean in a social context, then they can effectively give informed consent in this society. Makes sense to me.

It would prevent so many unjust and/or victimless convictions that a straight Age of Consent allows to happen.

- Rainbow