Boy/girl twins are always fraternal or (dizygotic); they can only form from two separate eggs that are fertilized by two separate sperm. The terms identical and fraternal dont describe what the twins look like, but actually how they form. Two girl twins: Can be either identical or fraternal (monozygotic or dizygotic)

How rare is a boy and girl twin?

Boy-girl twins are the most common kind of dizygotic twins, occurring 50% of the time. Girl-girl twins are the second most common occurrence. Boy-boy twins are the least common.

What is a fraternal twin brother?

Dizygotic (fraternal) twins Fraternal twins are, essentially, two ordinary siblings who happen to be born at the same time, since they arise from two separate eggs fertilized by two separate sperm, just like ordinary siblings.

Does your belly get bigger faster with twins?

Your belly may grow bigger, and you may gain more weight, sooner. Talk to your doctor about how much you might expect to gain. When youre carrying twins, you and your babies may be tested and checked more than you would for a single-baby pregnancy.