I've come across tons of articles and videos about or of pregnant transmen. I don't even know how, haha. I guess I like parenting so much that it subconsciously works its way into my interests. So, certainly other trans guys have desired pregnancy, and they don't see themselves as less manly because of it.
So here's what I've heard. Some people are rendered infertile after a certain time on T, others can get pregnant if they stop taking it no matter how long they've been on it (with the obvious criteria of not having had a hysterectomy). Perhaps that just depends on your body, so I don't think it's something you can predict. You have to stop T if you do get pregnant, because it could harm the fetus. I don't know anything more in-depth than this, though. Generally, being pregnant, you'll have to endure a few vaginal ultrasounds until they can start doing them on the skin of your belly, unless there are complications that require them to do frequent vaginal ultrasounds.
Does that help? I tried to cover as much as I could. Unfortunately, I haven't come across any scientific studies yet.