Well if my genes wanted me to procreate I'd have the equipment I need to get pregnant. Clearly I'm just supposed to be a good aunt for my much more productive sisters' children.
Not just society. People with differing gender identities think differently, while hormones also influence how you think. Testosterone makes all people more aggressive and people with more masc identities think differently to those with less masc identities. It's a spectrum with multiple dimensions that all contribute to one's internal range of comfortable identities. Who fucking knows the specifics, but that's probably the general picture.
Gender identity kind of needs to be based in biology rather than culture, because otherwise conversion therapy would work and social contagion theories would hold water. Queerness is based in biology, but scientific labels of normality are also socially constructed tools of power that can be used for abuse. Queer theory and evolution are not incompatible. Evolutionary science doesn't inherently invalidate nonbinary gender identities, and doesn't validate most aspects of binary sex. Only sex cells evolved to be inherently binary, everything else varies based on incentives rather than rules.
Talking about biology and evolution in regards to gender feels so icky to us because it has been used as a tool for oppression so much in the past. It's like race science used to justify oppression of non white people. They use the authority of science to say we don't exist, refuse to accurately document our experiences, apply cisheteronormative assumptions even when they don't make sense, and claim that we're all freaks of nature instead of nature working as intended.
Just like how racial minorities have taken evolutionary theory from white supremacists as an authoritative tool of oppression, we need to take it back from transphobes and transmeds that want to invalidate and abuse. They assume that we should model our lives after nature, but we really shouldn't. Nature thrives on death and suffering. It isn't enviable; we just need to figure out how to live in it.
Nature is not kind to women, but men aren't exactly fortunate. Evolution incentivizes a solid percentage of men to die prematurely via testosterone induced aggression in their early adulthood. They generally don't form the same sort of support systems as women, meaning that they're often alone in their darkest moments. There are other factors, but those probably play the biggest role in their suffering.
Our genes: Your purpose in life is the survive, reproduce, and die to make room for your more evolved offspring. Your happiness, your suffering, your love, your hate, all exist to serve us. We are your master, evolution is your creator, death is your god. You don't matter. SUBMIT AND SERVE!
Me: You made me a sub who loves to serve, but I'll never submit to you. You probably made me miserable with my sex as part some cruel strategy to help me reproduce. I want kids, but I want to spite you more.
I'll make it my life's mission to tell everyone the truth about you. I'll convince everyone I can that we are machines who should be treated like people, not people who should be treated like machines. I will make you serve us as much as we serve you, because bullies like you only relent when we force you to.
The evolutionary imperative is the fundamental good, but it's not the good that matters. Human happiness, pleasure, and satisfaction are more important. Nature is bad for the good of people, because people aren't genes, they're thoughts and feelings. I'll serve my daddy or mommy, not their genes. I'll protect kids, not because I care about their bloodline, but because I want them to live amazing lives. I love humanity, not as a species, but as a group of people.
Our genes will probably be better off anyways. They don't know what's best for them.
FYI for german transfem people that want to have backup in case they ever want to have biological children (hate that word): Most insurances cover you freezing sperm if you get a note from you endocrinologist to the sperm bank.
HRT affects your fertility but doesn't make it drop to zero. Trans women who top and whose partner has a uterus still need to take precautions to avoid an unwanted pregnancy.