I'm not aware that baby or toddler groups were gendered. We had grandads, grandmas, dads, mums, and foster carers (gay and straight) and even a childminder at mine in my not especially cosmopolitan grim northern town. Sometimes the same child would come on different weeks with different carers, depending on what suited the family. No one asked, we just chatted about kids, drank tea and found people to hand down outgrown clothes to. It was a bloody lovely group, bit labelled as 'inclusive' but really it was very supportive to everyone's circumstances, with no oppression Olympics.