CONCLUSION
If marriage is our solution to the social problem that every society must solve, and must be between a man and woman then the conservative conclusion is that gender identity should not be used as a legal basis of classification replacing biological sex.
Michael Mascolo Ph.D. lays out the issues with self-identification:
The point here is not that one’s personal experience is irrelevant to one’s identity—it is indeed foundational. The point is that it is simply not sufficient. We need more than what someone says in order to establish and verify an identity. We need to be able to point to public and shareable expressions of the person’s experience in order to verify the person’s identity. A person can claim an identity as a Democrat, but without voting for Democrats, espousing Democratic principles and acting on those principles, a person’s self-identification has no warrant.
https://www.psychologytoday.com/gb/blog/old-school-parenting-modern-day-families/201909/gender-why-self-identification-is-not-enough
A PUBLIC POLICY COMPROMISE
Individuals should be free to self-identify however they wish, though this identity should not be enforceable on the rest of society.