I read somewhere that identical twins were 1 in 250... And fraternal twins were 1 in 80... I think the numbers increase to 1 in 60ish when you include medical interventions like ivf and hormone treatments ect.
Not very common. Fraternal twins are usually genetic (only one the mothers side) and are caused by hyper ovulation (more than one egg drops when you ovulate) and identical twins are from a fluke where the egg splits in half.
Girl, I don't even want to think about it. Lol! Going for first ultrasound in a few days and kinda nervous as twins run in my family.