At the moment transwoman could have sperm frozen and transguys have eggs frozen, prior to HRT etc.. So at any point they could have a surrogate carry a child for either of them with a partner of their choice in the future. They would of course need an egg or sperm donor to complete the process but anonymous sperm donor banks already exist, I'm not sure about egg banks though.
For carrying or fathering a child respectively, I'm not sure that will be in the near future. Not a lot of society interest to drive it.
Cindy