Even though almost all primates today give birth to one baby, our most recent common ancestor, located in North America around 60 million years ago, probably gave birth to twins as the standard.

Ancient Rome was a man ... to keep newborn babies. After birth, the midwife placed babies on the ground: only if the paterfamilias picked it up was the baby formally accepted into the family.

Almost all primate species give birth to just one baby, although there are exceptions ... two babies at once was the norm. Our ancient primate ancestors gave birth to twins.

Although twins are rare in human society, and non-human primates usually only give birth to one baby per litter, a new study from the United States has shown that twins were not uncommon in the ...