09/16/2016 — 1 out of every 4 births due to IVF treatments will be twins. How parents and society raise and treat twins, either as a “twinship” or as individuals, makes a big psychological/health difference as twins try to seek independence from one another and build separate friendships, careers, and romance. Dr. Joan Friedman, one of the country’s foremost experts on twins and author of "THE SAME BUT DIFFERENT: How Twins Can Live, Love, and Learn to Be Individuals," discussed.