Beatie, 34, gave birth to a girl called Susan Juliette three weeks ago after 40 hours of labor, with his wife Nancy at his side acting as his coach.
"When Susan finally came out, it was like in slow motion," said the transgender man. "I was full of wonder." Echoed Nancy: "There were tears of joy."
"She's so precious, I just can't stop staring at her," he told People. "Just holding her is the best feeling in the world."
Beatie is legally male but was born female and underwent gender reassignment surgery and hormone treatment.
Susan, named after Beatie's mother, was conceived through artificial insemination with donor sperm when the couple decided to have a child.
Nancy is breastfeeding the baby though a process called induced lactation.
More than five-month pregnant transgender man Thomas Beatie (R), 34, sits with his wife Nancy on Oprah Winfrey's talkshow "Oprah" Thursday. He told Winfrey, "it's a human desire. And I'm a person, and I have the right to have my own biological child." Thomas and Nancy have been married for five years, and have been trying to have children for two years, but Nancy is unable to bear children due to endometriosis.