But last week Beth Israel started seeing double. Six moms had two babies each.
"We've never had six sets of twins born in a day before," a hospital spokesman said.
It may be the biggest one-day crop of twins a hospital has ever had.
Two of the world's oldest twins, Keen and Geen, just turned 106. For their birthday party in Japan, everyone shared a huge cake and orange juice.
From 'In The News' with CBS News Correspondent Dan Raviv. ©1998, CBS Worldwide Inc., All Rights Reserved