Lenny's intersex and repressed transfem. He can be born with either nuts or a vag. Either way he's raised as a boy by his parents, grows up looking boyish despite having boobs, and is socialized to repress his femininity. Even in the future, he's stubbornly reluctant to let himself be happier as a girl until many months into HRT 😭 hardboiled egg, hardstuck deep in the closet bc of how severely he was bullied at school & home for being a girly boy.
He has the legal name Nina because they thought he was going to be a girl before he was born. His mom really wanted to name her incoming daughter after her late mother. However once he was born his genital situation was too ambiguous to confidently declare him "female". While his sex assignment was in contention, his name was in stone; even after "realizing he's a boy," his mom REFUSED to change it bc of its sentimental weight.
Lenny's dad subconsciously holds this against him. He feels his legacy's been stolen, cheated out of getting a "Glenn Jr" (or I guess Glenn III since his dad is technically Glenn Jr.... Lenny's dad just wanted a junior of his own). Especially since their further attempts to have kids all failed, he's a bit resentful of Lenny, he sees him as "defective". He strives to mold Lenny into the son that he wanted rather than accepting the one that he got, imposing strict male gender expectations on him extra hard to "make up" for how he was born :/ + he makes fun of him for his birth name too 😭 if he didn't get any control in picking his name he'll at least try to influence how Lenny feels about it, and boy is he vindicated by how much Lenny ABHORS his birth name.
TLDR: Lenny's MTF with extra steps