Number of twins being born globally at 'all-time high', medical study shows Posted FriFriday 12 More than 1.6 million twins are now being born every year, researchers say. ( Share Print text only Cancel Almost one in 40 children are being born twins — more than ever before — mainly due to the rapid rise of medically assisted reproduction, according to new medical research. Key points: As did mothers giving birth at an older age, when twinning rates are higher Researchers gathered data from 135 countries from 2010-2015 More than 1.6 million twins are now being born every year, researchers said in a paper published by scientific journal Human Reproduction.