5-year-old Reuben Blake and his seven-week-old sister Floren from UK are twins that arrive five years apart.
Both children were born from the same batch of embryos created during their parents’ IVF treatment.
While Reuben was successfully implanted in 2006, Floren was kept on ice until 2011.
Now their parents, Jody and Simon Blake, delight in telling well-wishers all about the incredible age gap between their “twins”.
“I tell everybody I can,” said Simon Blake, a business lecturer.
“People take an interest in a newborn baby and with Reuben around as well, I find it very difficult to resist the temptation to say <<Oh and by the way, they are twins>>.
“It’s almost just to see people’s response. They are really amazed and surprised.”
Jody Blake, a charity worker, added: “It does feel quite surreal.
“I think people are really, really surprised and it almost takes them a few minutes to get their heads around it.
“We obviously had nine months to get it straight and to think <<Gosh, we’re having Reuben’s twin>>, but it’s incredibly special.”
Jody Blake, 38, and her 45-year-old husband began fertility treatment in 2005.
During the medical process, five embryos were created and two implanted in Jody Blake, which resulted in the birth of Reuben on December 9, 2006.
The remaining three embryos were frozen until the couple, from Cheltenham, Gloucestershire, decided to try for another child in March 2011.
Only one of the embryos survived the defrosting process and 39 weeks later Floren arrived by Caesarean section.
Reuben is fascinated by his little sister. “He knows that she’s been in the freezer,” said Jody Blake.
“He likes to say she has been in the freezer with the chips and the chicken, so he is sort of aware that she is his twin, but obviously he doesn’t really understand how it’s all worked.
“They do look very similar. Reuben was just a bigger version of Floren when he was born, so certainly there are similarities physically.”
Recalling their decision to try for a second child, Simon Blake said: “We wanted to complete the family. We were aware the odds were long.
“You just can’t comprehend that a life could come from some material that’s been frozen for that length of time.”
Doctors who treated the Blakes at the Bristol Centre for Reproductive Medicine said the decision to freeze remaining IVF embryos was a safer way to have more than one child.
Lead clinician Dr. Valentine Akande said: “We very often recommend storing surplus embryos so that they can be used at a later date.
“Sadly, due to the chance work of nature, not everybody is able to have those surplus embryos and, of course, not everybody meets with success when they are used.”