According to the world's foremost source of impeccably researched reference material, the term "twins" is defined as " a strong thread or string composed of two or more smaller strands or yarns twisted together. "

But in honor of Mary Kate and Ashley Olsen's 21st birthday, we at Barstool would like to pay tribute to those other kinds of twins. The kind that result when two fertilzed eggs are implanted in the uterine wall at the same time and are independently fertilized by two different sperm cells.

Again according to Wikipedia, there are two types of twins, Fraternal and Identical, but we at Barstool would like to take this occasion to honor our other, more favorite categories:

Drunken, Powerful, Embarassment-to-the-Family Twins

Jen and Barbra Bush

To see more useless pictures of famous twins, click here...