Friday the 13th: The Series (1987) : 3x19

An exclusive fertility clinic is much mroe than it seems. It is run by a cult of female Druids who use a cursed fertility statue to expand their numbers. When infertile couples come to them, they use a ritual that kills the husband and results in the birth of twins: a boy and a girl. They only tell the mother that one child was born, and turn over the boy. They keep the girl to raise as a Druid priestess. A friend of Micki's is undergoing treatment, leading the trio to the clinic. They manage to break up the statue before the Druid priestesses can use a ritual to cause the fertility statue to replicate. The head Druids die, and the trio manage to reunite the young girls with their true mothers.