Research at Mayo Clinic has led to a first in Minnesota — babies born from eggs that were frozen, then thawed before being fertilized in a petri dish.

The Star Tribune reports that healthy twin girls — Elizabeth and McKinney Caudill — were born in early June.

Egg-freezing is growing as a way to preserve fertility for women. For the twins' parents, it was a way to avoid the emotional decision of what to do with excess frozen embryos that will never become children.

The twins' parents, Ceresa and Jonathan Caudill, were reluctant to freeze embryos if those not used in in-vitro fertilization might be destroyed.

So far, only 200 to 300 babies have been born from frozen eggs worldwide.

Mayo will now provide the service to anyone for whom it is appropriate, including women who simply want to delay child bearing.