(CNN) -- Two sets of identical twins born were born to a Texas family on Valentine's Day.
Ace, Blaine, Cash and Dylan were born in Houston on Feb. 14. to Tressa Montalvo and her husband, Manuel. The couple said the twins were not the result of fertility treatments.
The twins were not the result of fertility treatments, the hospital said. Tressa Montalvo learned she was carrying twins at 10 weeks.
The identical twins resulted when a fertilized egg split into two embryos. Twins occur in abou 2% of all pregnancies and 30 % of those are identical twins.