The odds of being born on Leap Day are about 1,400 to one. The odds of natural quadruplets are more than 700,000 to one.
So what's the chance of having quadruplets on Leap Day? About 3.5 million to one, according to doctors who delivered quadruplets Reuben, Zachary, Joshua and Samuel Robbins this week on Feb. 29.
Emma and Martin Robbins welcomed their four sons -- two of whom are identical twins -- about 11 weeks ahead of their scheduled due date, the BBC reports.
According to the Bristol Evening Post, the boys were delivered by Caesarean within six minutes of each other and arrived healthy, despite being underweight. The smallest boy, Zachary, weighed just 2 pounds 8 ounces at birth, while the largest of the set, Joshua, weighed 3 pounds 1 ounce.
Martin Robbins told the paper that though he and his wife were worried when they first learned they were having four boys, they opted against "selective reduction," the practice of terminating one or more fetuses in a multiple pregnancy.
“I think that things happen for a reason, and that we are blessed. Deep down at the bottom of my heart I know that we will find a way of coping," Robbins told the Bristol Evening Post. "Emma is a project manager, so if anyone can deal with having quads it will be her."
Emma Robbins has been keeping a diary of her pregnancy on her blog "Emma's Quad Diary."
Read the full report on the quadruplets' birth from the Bristol Evening Post and check out the BBC's video interview with the family above.