College Girls Discover They're Half-Sisters by the Same Sperm Donor
01/24/2014 AT 08:45 AM EST
The Tulane University freshmen met last fall and didn't think too much of it when each told the other she'd been conceived by an anonymous Colombian sperm donor.
But at the urging of Stern-Ellis's parents, they did a little investigating – and discovered it was, in fact, the same sperm donor.
The girls had already been joking with friends about being related, but never thought it was true. "We've been telling people, 'Oh, there's a 25 percent chance we're sisters,'" Nappi tells the Tulane Hullabaloo student newspaper.
The half-sisters now realize there might be a genetic reason why they love the same things, including acting – an interest that the donor also listed on his profile.
"For me, Tulane just felt right, and this is one of the many things that proves I made the right decision," said Stern-Ellis.