The last time the Underdahl family of Post Halls, Idaho, welcomed a baby girl was way back when in 1914. But the 102-year all-boys streak has finally been broken. On April 12, little Auerelia Underdahl was born to Scott and his wife, Ashton Underdahl. (Scott, for the record, is one of four boys.)
"Everyone has been hoping for a girl," Scott told the Coeur d’Alene Press. "I didn't know what an Underdahl girl looked like."
The Underdahl family isn’t the only one to have a long string of sons. Last year, the Mays of Mayo County, Ireland, celebrated their first girl in 117 years. And in 2014, the Lawries of Kent County, England, welcomed their first girl in 200 years.
So what’s behind the bevy of boys in certain families? To explain, here’s a quick refresher on chromosomes and gender: It’s the man’s sperm (carrying either an X chromosome for female, or Y for male) that determines the sex of a fetus. Some men produce more Y sperm than X sperm, resulting in more sons. (Conversely, some men produce more X sperm than Y, which results in more daughters, while still others have an equal number of X and Y.)
If you’re curious about your own chances of having either a boy or girl, look to your husband’s family for clues—if he has a lot of brothers (à la Scott Underdahl), there may be a son (or two ... or three) in your future.