I don’t know, I doubt there have been stats collected in such things. They do exist though.
I’m currently in a lesbian. relationship with a trans woman, and we just had a baby together. She is the predominant bread winner, and a committed care giver to our daughter. My girlfriend transitioned as a young adult. I have met at least 2 other parents who are trans women, one of them was a single parent.
My comment though was about gender dysphoria, not parenthood. I don’t believe in having a hardship war here, debating which is worse, being a single parent vs living with gender dysphoria. The two are simply not comparable by any measure- they are radically different.
I do know however that gender dysphoria is very painful, and I have lost people in my life to it. Every trans person I know has made it clear they never chose to be trans or experience gender dysphoria, and they felt they had two options, transition or suicide. I’ve known a lot of people who chose the second option, and many who have chosen the first. I think a lot of people who don’t experience gender dysphoria don’t see it, understand it, or really understand it exists. Some people flat out don’t believe it exists because they don’t experience it. But it has taken many people, is very painful, and is very much real. What are trans people who experience dysphoria supposed to do? Is it so wrong that trans people are just doing what they need to do to relieve the pain of gender dysphoria?

True, trans women are not likely to get pregnant on accident or find them selves single parents on accident. I can admit that is privilege they have over AFAB.
However that doesn’t negate the fact that they experience debilitating dysphoria, and cis women like JKR have no idea what that is like, and that’s privilege as well. Both exist, it’s not a completion which is worth. Being aware of differences and how they effect each sides perception is important if they are to understand each other and their actions.