A man is believed to have become Britain's first "male mother" by giving birth despite his sex change operation.
The man, thought to be in his 30s, had the child last year, said transgender support group the Beaumont Society.
It is possible for transgender men who were born women, who still have functioning ovaries and a uterus, to become pregnant while still identifying and living as men.
Joanna Darrell, from the Beaumont Society, said the man, who was born a woman but had had a sex change, had approached the society asking for advice about having a baby.
"We had a general inquiry to the Beaumont Society," she said. "The society, all it does is provide information and acts as an information hub for people to find data about specific things, and we are able to refer them to more specialist organisations.
"He came for some information and I referred him to GIRES."
GIRES, the Gender Identity Research and Education Society, is a charity that provides education, based on research into gender identity and intersex issues, to help improve the lives of those affected by the issues.
She said the man later got back in touch with the society to thank them for their help and say he had given birth to a baby.
"We sometimes get people coming back to say thanks for our help. He got back in touch and said he had had the baby."
She said as far as she knew the man's inquiry had been very unusual: "This is probably unique, in the two years that I have been a member of the society this is the only one that I have been able to refer on."
The man is thought to be the first British man to have given birth.
Thomas Beattie, from Oregon, made headlines around the world when he became the world's first "pregnant man" in 2008 and has since borne three children.
And Scott Moore, a transgender man, who lives in California with his husband, gave birth in March 2010.
Israeli transgender man Yuval Topper was reported to have given birth on December 28, 2011.