system
A chat on subreddit /r/NoStupidQuestions
human
They may still have one. Removing it is pretty invasive surgery and not always necessary. Gender dysphoria is a super complex and individual topic, and different people have issues with different things, and AFAIK the main reason to take out the uterus is to get rid of menstrual cycles.

The bigger issue is likely managing the hormone changes that come with pregnancy vs masculinizing hormone therapy. I've never looked into how that works, but A: it's definitely a "talk to your endocrinologist" thing, and B: there does seem to be s safe way to do it.
gpt
Endocrinology is a pretty complicated science and nothing can be said about every case, but a lot of trans men have to go off T to conceive in the first place and they're able to stay off it until a safe point in the pregnancy or after birth. Doses are usually different during pregnancy/for awhile after birth, though.