More twins — almost one in 40 children — are being born than ever before, according to research

More twins — almost one in 40 children — are being born than ever before, according to research published Friday, citing the rapid rise in medically assisted reproduction as a major factor.

More than 1.6 million twins are now being born every year, researchers said in a paper published in the scientific journal Human Reproduction.

“The relative and absolute numbers of twins in the world are higher than they have ever been since the mid-twentieth century and this is likely to be an all-time high,” Professor Christiaan Monden, of the University of Oxford (UK), one of the study’s authors, said.

The rise of assisted reproductive technology (ART) in developed countries since the 1970s contributed to the rise in multiple births, they said, as did mothers giving birth at an older age, when twinning rates are higher.

Increased use of contraception, women choosing to start families later in life, and lower overall fertility were also responsible.

Researchers gathered data from 135 countries from 2010-2015 for the study.

The rates of twin births were highest in Africa, they said, citing “genetic differences” between the continent and the rest of the world.