Expert: Lawrence Jay Rappaport <B>M.D.</B> - 1/2/2005
Question HI,
I was just wondering if I'm next in line for twins. My mothers grandfather was a twin. When she was pregnant with me the doctor told her she was having twins only to find out later that was false. But because she didn't have twins my Biology professor told me that it could increase to triplets for me? Is this true? Hopefully you know the answer. Thanks.
Answer "Identical twins" are the result of the division of a single fertilized ovum. Identical twins occur in 2-4 out of 1000 pregnancies in all races. It is NOT influenced by heredity, age of the mother, or other factors. "Fraternal twins are produced from separately fertilized ova. Around 70% of twins are fraternal, and 30% of twins are identical. Fraternal twins occur once in 83 pregnancies and triplets occur once in 8000 pregnancies. Fraternal twins can be found to run in families. Your Biology professor is incorrect and there is no increase in the incidence of triplets by skipping twins in any generation. There is no formula to determine who will have twins, triplets, or singletons. Triplets are exceedingly rare and do not run in families.
