Kat Cooper, a gay detective, successfully led the fight that culminated in the Collegedale City Council approving the extension of benefits at a meeting Aug. 5.
Kat Cooper's mother, Linda, stood by her daughter throughout the process, the Times Free Press reported.
On Sunday, the leaders at Ridgedale Church of Christ met with Kat Cooper's mother, aunt and uncle after the weekly service.
Linda Cooper said the leaders told them they could either repent for their sins and ask for forgiveness in front of the congregation, or leave the church.
Ken Willis, a minister at the church, said the family's support of Kat Cooper was an endorsement of homosexuality.
Linda Cooper's parents were involved in the founding of the congregation, and Kat Cooper told WTVC her family has attended the church for more than 60 years.
CNN said Churches are Christ are loosely joined groups of local institutions, and ministers at the churches are largely able to set the tone.