A woman in Houston gave birth to two sets of identical twins in one day on February 14 -- Valentine's Day, no less! -- and in the process made a mockery of statistical probability.
The pairs of twins -- both sets boys -- were born to 36-year-old Tressa Montalvo, who pulled off the feat without the aid of fertility drugs. The Woman's Hospital of Texas, where the delivery took place, said the likelihood of a birth of pairs of identical twins at one time was around 1 in 70 million. Late in her first trimester, Montalvo thought she'd be having twins, but later checkups revealed four babies, two sets of twins, each pair sharing a separate placenta. The babies were delivered by Cesarean section.