I did it twice. And it was the weirdest and happiest thing I have ever done. I was in denial at the time, I knew (deep, deep down) that I was trans but I thought that I was so committed to the female identity that I had been putting on for so many years that I just had to soldier and try to be a woman. But I was definitely never, ever going to have children. I hated everything about my female biology, and I was utterly terrified of getting pregnant. Then, at age 38, I realised that I was going into early menopause, and that the window was closing. And I realised that I really, really wanted to have kids. My partner and I decided together that we would both probably regret it if we didn't have children, so I got pregnant, and then just held on for dear life, like I was on some out-of-control 9 month long fairground ride. I was actually disassociating so much that it didn't really seem like it was happening to me. It was like watching a movie while throwing up a lot. But the birth almost killed me. I couldn't handle it, so I fought it, which is the worst thing to do. It was 36 hours of mental destruction. I will not include gruesome details. But I lived, and a had this wonderful baby. She was a tiny miracle, and I have never had so much joy in all my life. So, two years later, I did it again. I now have two beautiful, amazing children, and I still don't know how I did it, but I am really, really grateful that I did.
In a weird way, it was the start of me coming out. My fake female persona had been so broken down (sleep deprivation will do that to you) that I decided to just abandon it, and be realistic about who I really was.
Last week I came out to my kids (I had previously only told my partner and close friends), and they had this amazing non-reaction. My eldest daughter said, "Why did you ever think that we would be worried about that?" and the little one said, "Yeah! We don't care if you grow a beard."
So obviously it won't work for everyone. But it worked for me.