A US mother has defied odds of 70 million-to-one by giving birth to two sets of identical twins on the same day.
Tressa Montalvo's four newborn sons were delivered by Caesarean section at a women's hospital in Dallas, Texas, on Valentine's Day.
The 36-year-old and her husband Manuel, 43, had planned on having another child to give their two-year-old son a little brother or sister.
But they were shocked when a doctor shared the news they would be expecting four.
"I just couldn't believe it. If I wasn't already lying down on that table, I would have been on the floor," Mrs Montalvo told news station KHOU.
The four babies — Ace, Blaine, Cash and Dylan — were conceived naturally without any fertility drugs or IVF.
However, because these babies came from two eggs, it would be a mistake to call them quadruplets, which generally come from four separate eggs.
With identical twins, a single egg splits and forms two embryos just before it implants in the uterus. Around two percent of all pregnancies result in one set of identical twins.
In Mrs Montalvo's case, two eggs were fertilised and then decided to split before they were implanted.
The chances of that happening are somewhere around one in 70 million, obstetricians said.
With five sons now in the family, the Montalvos said they would still like to try having a girl.
Author: Erin Tennant, Approving editor: Mark Worley