The gay couple that caused an uproar when they became the UK's first surrogate gay dads say they are expecting a fourth child, the UK's Mail Online reported.

Barrie and Tony Drewitt-Barlow received international attention in 1999 when they traveled to the United States and participated in the IVF procedure that produced twins Aspen and Saffron.

The couple became fathers for the third time four years later with the birth of Orlando.

“I am really looking forward to Father's Day this year,” Barrie, 40, said.

“We had the pregnancy confirmed and we are going to find out today whether it's a singleton or whether it's a twin pregnancy. We know we are pregnant but we don't know how many yet. The baby is due on Valentine's Day.”

The Chelmsford, Essex couple drew controversy when they became the first gay couple to be jointly named fathers on their children's birth certificates after a lengthy legal battle decided by the U.S. Supreme Court. The pair, who became millionaires in 1998 when they sold their clinical research company, entered into a civil partnership in 2006, soon after returning to Britain from living in Spain.

The gay dads attempted to adopt a child before they investigated surrogacy, but despite glowing references by their social workers they were denied twice.

Barrie told the paper that the new baby's egg donor was a Japanese woman from San Francisco, and they were using the same surrogate mother who gave birth to Orlando.

The Drewitt-Barlows, who have been accused of designing babies with past pregnancies, said they left the sex of the baby to chance.