Dependent Visa with my “same sex” partner

Hey all,

Was just perusing the wiki as I have been trying to see how possible it is for my partner and I to move to Japan someday. American citizen here.

I saw that you can have the Dependent Visa if your spouse/parent/etc has a work visa in Japan (please correct me if I'm misunderstanding)!

However, my partner is a trans man and so we are technically the same sex. On his legal paperwork, he is now documented as male, and I am documented as female.

Does birth sex matter? Can we move to Japan using dependent Visa if one of us is working, even if same sex couples are not recognized/he is transgender?
Thanks for your help!

Edit: additionally, I have considered changing my gender marker to X. Would this put a detriment on my moving there? If so, I would keep it as F.

by wormsinpeaches