Yeah, there's a few ways your gender can be locked. Pregnancy and prolonged bimbo are two of them. There's character specific ways like Dom John forcing you to be a bimbo and Sophie's "secret" dom route forcing you to be a sissy.
A male acting feminine will progress from male to trans to female.
A female acting masculine will progress from female to trans to male.
A submissive trans can become a sissy.
A constantly horny female can become a bimbo.
Trans/sissy bimbo used to be a thing as well as a trans dom "gender" called "shemale" but they've since been removed.
Changing gender identity in the bathroom and dressing a certain way are good for passively gaining masculinity or femininity every night. Some accessories like the chastity cage and the cat collar greatly increase sub. Apart from that it's pretty much all about what sexual activities you consent to/engage in which you have the option to do depending on the routes you dose NPCs down.
;
