A New York fertility doctor claims a protege poached his clients by opening a competing clinic.

John Zhang, once labelled a “fertility rebel” for creating an embryo with DNA from three parents, says former employee Dr. Mingxue Yang has been acting like a rotten egg, according to a Manhattan Supreme Court lawsuit.

Mingxue Yang worked at Zhang’s New Hope Fertility Center for a decade before leaving in February to open his own facility, despite allegedly agreeing to avoid competing with Zhang for six months and to keep any new business at least five miles away from Zhang’s two Manhattan locations in Columbus Circle and the Upper East Side.

Instead, Yang posted on a social media platform popular with Zhang’s patients, alleging his boss had locked him out of New Hope and was “unappreciative” of him, Zhang claims.

He made it seems [sic] like he was fired instead of resigning,” according to court papers.

Yang began setting up Legacy Fertility IVF, on Third Avenue, before he even offered his resignation, and he has taken in more than 10 of Zhang’s patients, Zhang charges in the legal filing against Legacy IVF.

Zhang wants $6 million in damages from Legacy IVF for defamation and unfair competition. Lawyers for Legacy IVF didn’t respond to messages.