My boyfriend is in college, & doesn't believe it's possible for healthy ovaries to both release a egg for the same ovulation day. I explained this thing can happen resulting in fraternal twins.. But he will only believe a professional. Can you help?

Fraternal twins are created when a woman releases 2 eggs and both are fertilized. Identical twins, on the other hand, happen when one egg is fertilized and it splits.

Yes it's possible, or we wouldn't have multiple non-identical births, and it's all healthy. We are born with around 5 million eggs. By our teens, we have 200,000 or 300,000 left, with many dying as we age. The ones left lie dormant within the ovaries. At the beginning of each menstrual cycle, the pituitary gland sends FSH (follicle stimulating hormone) to stimulate a small number of eggs (not just one!) in the ovaries to start maturing in a tiny capsule of fluid called a follicle. After two or three days one of these follicles is 'selected' by physiological processes to be the one that will ovulate. The other eggs which had started maturing will spontaneously regress. But the egg has to travel, so there's no way to know the exact moment that a follicle will meet a sperm after it is formed and released, and occasionally more than one will ovulate, from each ovary or both. Nature loves to make babies, but she isn't always exact and consistent.

Want to surprise him even more? Not only can both ovaries release an egg at the same time, you could have two eggs release and become fertilised, then one splits. Now you have triplets... two identical, one fraternal.

You could have two eggs released, the woman has two different encounters close together, and the eggs can be fertlized by different fathers.

Even more unusual would be a second cycle occurring within a few weeks after the first and both resulting in a pregnancy. Now you have two babies developing at different stages who are not actually twins.

Amazing bodies, eh?