Hence why religious fundamentalists should embrace transsexuality and normalize it.
In a society where a biological male might identify as female and therefore women might also have beards, you could be sure if a person was a man or a woman based on things like their beard. That cute woman on the walk home could be a man. That cool dude at the gym could be a woman. You wouldn’t be able to gaze lustfully at anyone while assuming their gender. Religious fundamentalists also tend to live arranged marriages or pairings through the church. If you can no longer tell gender you can no longer tell sexuality. The only people who would know what was in your pants now or when you were born would be people close like family or clergy and such. Therefore to make sure you weren’t “picking wrong” you’d be incentivized to wait for someone close to you to match you with someone close to them- like a clergy introducing two people or two close families.
This would preserve and protect close community binds while discouraging both impure thoughts and deeds with strangers. Since you would only know gender and sexuality through introductions by people mutually close enough to know those things about both people being introduced, no strangers would actually know. Is this two men with beards holding hands or two women with beards or a man and a woman? You don’t know. So even if you preserve common religious fundamentalist beliefs about homosexuality- the entire concept becomes unenforceable and a non issue in the community as it is only really known for sure to your god(s) and the persons involved and can be between them to settle up on it.
In a society where a biological male might identify as female and therefore women might also have beards, you could be sure if a person was a man or a woman based on things like their beard. That cute woman on the walk home could be a man. That cool dude at the gym could be a woman. You wouldn’t be able to gaze lustfully at anyone while assuming their gender. Religious fundamentalists also tend to live arranged marriages or pairings through the church. If you can no longer tell gender you can no longer tell sexuality. The only people who would know what was in your pants now or when you were born would be people close like family or clergy and such. Therefore to make sure you weren’t “picking wrong” you’d be incentivized to wait for someone close to you to match you with someone close to them- like a clergy introducing two people or two close families.