Doctors behind 1st US baby born from a uterus transplant describe the 'beautiful' medical milestone A doctor said it "totally changed my mind about many things I thought were set."

 -- The doctors who helped deliver the first American baby born from a transplanted uterus opened up about the medical milestone, one of them telling ABC News, "this little boy will stay with us for our entire life."

"It was a beautiful thing to watch," Dr. Giuliano Testa, the surgical chief of abdominal transplantation at Baylor University Medical Center in Dallas, told ABC News.

His colleague, Dr. Liza Johannesson, added that "all of us had tears in our eyes."

"This little boy will stay with us for our entire life," Johannesson said. "He's one of us."

The baby was born last month to a mother who had been born without a uterus, and received a transplant at Baylor University Medical Center, last September as part of an ongoing study. The woman suffered from Absolute Uterine Factor Infertility, a type of infertility affecting approximately 1 in 500 women, where the uterus is non-functioning or nonexistent.

"It was very special to look in the eyes of the mother, she was told when she was a teenager that she would never see this moment and then all of a sudden you see this happening and you think everything has meaning," Testa said.

The baby is now the ninth baby born in the world from a transplanted uterus, joining eight other babies successfully born from transplanted wombs in Sweden.

As part of the ongoing study at Baylor, researchers have completed a total of eight uterus transplants, including the one in the mother who just gave birth. While three have been unsuccessful and one woman is currently pregnant, the remaining four women are in different stages of the transplant process, and doctors say the baby offers them hope.

"This birth and this boy is giving hope to all these women out there who have this type of infertility and that is truly an amazing thing," Johannesson said.

Testa added that the successful birth "was really something that totally changed my mind about many things I thought were set."

"People like me, or men in general, don't really talk about this, because we don't know any better, but one thing that we all learned is that we should never have underestimated the need, the will, the wish, of the woman to carry their own pregnancy," Testa said.

"It's been humbling and I have a better understanding, I hope about these things and I can really say today that this is a solution, this is something that has value for this woman, for all of us," he added.