Thandi Schweitzer and her partner Deb Rousseau moved into the two-bedroom Magnolia Gate condo six years ago, aware of the age restrictions, the Vancouver Sun reported.
But in recent months they and at least two other residents of the building have had children and management has given them all the same warnings.
The couple was told in September, three months after their baby was born, they either had to leave or face fines of $200 per week beginning in March.
Schweitzer told the Sun she and her partner feel their human rights have been violated.
"I think it's extremely unfair," she said. "I feel really marginalized. It's just so un-Canadian."
Age discrimination in the Canadian province is legal and challenges to it have traditionally been tossed out by the British Columbia Supreme Court.
Additionally, the Canadian Mortgage and Housing Corp. won't give mortgage insurance to residents of age-restricted housing because their resale value can be as much as 20 percent less than unrestricted units, the report said.