Today we discuss how Twins are formed!
Twins can either be identical (in scientific usage, "monozygotic"), meaning that they develop from one zygote that splits and forms two embryos, or fraternal ("dizygotic") because they develop from two separate eggs that are fertilized by two separate sperm.
The Yoruba have the highest rate of twinning in the world, at 45 twins per 1,000 live births, possibly because of high consumption of a specific type of yam containing a natural phytoestrogen which may stimulate the ovaries to release an egg from each side.
The degree of separation of the twins in utero depends on if and when they split into two zygotes.
And don't even get me started on TRIPLETS!