what percentage of the population has identical twins
Twin The human twin birth rate in the United States, rose 76% from 1980 through 2009, from 18.9 to 33.3 per 1,000 births.[5]
Abby and Brittany Hensel Abigail Loraine "Abby" Hensel and Brittany Lee Hensel (born March 7, 1990) are American dicephalic parapagus twins; in other words, they are conjoined twins, each of whom has a separate head, but whose bodies are joined. They are highly symmetric for conjoined twins, giving the appearance of having a single body without marked variation from normal proportions. In fact, several vital organs are doubled; each twin has a separate heart, stomach, spine, pair of lungs, and spinal cord.