I would love to see more transgender main characters.  There’s a series that’s supposed to come out on the CW with a lead transgender character, which I am cautiously optimistic about (cautious because CW is hit or miss).  We actually have a trans character coming up in our book series.  We plan on doing a lot of research going in, because we don’t want to misrepresent anyone.  We have a good friend who is actually in transition right now (male to female) and she’s been more than willing to talk to us when we reach our character.  The last thing I want to do is misrepresent an underrepresented group.

This is a random anime example, but look into Grell from Black Butler.  It’s Victorian era, but Grell is canonly a man who wants to be a woman.  The creator did interviews with her characters and Grell actually said something along the lines of thinking God made a mistake in making “her” a man, and Grell always refers to herself as a lady.  She also wants a family and children.  Of course, the 1800s don’t really have the resources for such a thing (I think?  I’m fairly certain they don’t, but that doesn’t mean that trans people didn’t exist, or maybe even extreme measures were taken?  I think you can pull this off in your book, you just need to do research).