[ericmay]

Mothers like mothers in porn? Mothers giving birth? Grandmothers? What about animal mothers? What about fathers in videos with mothers? Are the mothers giving parenting or medical advice? Who is policing the filters and deciding what constitutes a video about mothers?

And either way, why bother? Just don't recommend content there's no point except to drive engagement which is fundamentally no different than what Facebook (or whoever) is doing.