A British family is celebrating an usual milestone -- the birth of a fourth generation of twins.
Melanie Gwynne, who has a twin sister, is now a mom to twin girls, Jessica and Clara. Gwynne’s dad and grandma are also twins, according to the Bristol Post.
“My dad always said it's more fun having two,” Gwynne told the paper. “Me and my sister always knew one of us would have twins, we just had a feeling. Now it's me I think she is relieved it's not going to be her. I think one of my girls could have twins, it would be nice if they kept the tradition going."
The family was featured on the British documentary, “One Born Every Minute.” The documentary team followed Gwynne as she decided whether to have her partner or her twin sister, Sherrill, help with her delivery of the twins.
Gwynne said her dad was so excited that both his daughters and his granddaughters were twins that he has reached out to the Guinness Book of World Records to see if it was a first.
ABC News was unable to reach Gwynne for comment. But experts say she shouldn’t count on her daughters having another set of twins.
Dr. Jaques Moritz, director of Gynecology at Mount Sinai Saint Luke’s Hospital in New York, called the multi-generation twins “pretty damn rare,” and didn’t guess as to what the probability would be. Twins naturally occur during 1 percent of pregnancies, he said.
The Gwynne twins may be a coincidence, Moritz said there’s a chance that an environmental factor may have boosted the odds. He explained how an African tribe called the Yoruba has the highest twin rate in the world. Some scientists believe that the tribe’s yam-rich diet causes women to release multiple eggs during ovulation, he said.
“Non-identical twins are influenced by cultures and other factors,” said Moritz. “Maybe it’s something in the area that they live in or genetically or it causes them to ovulate twice.”
As for the old wives tale that twins skip a generation? Moritz said it's a myth resulting from the rarity of natural twins.
“It’s like going to Las Vegas and you can get three cherries [in a slot machine],” said Moritz. “The chance of getting it two or three times in a row is pretty rare."