I was recommended Mermaids when my eldest son was small. He loved dolls, wearing fairy dresses, wanted to be a princess, doll, and was often mistaken for a girl. As a feminist, I had resisted gendered toys and was happy with all of his behaviours, as it was clearly who he was.
#Mermaids was sold as a playgroup for gender non conforming kids. I thought it would be boys in frocks running around, girls digging holes & climbing, and some fairy princesses driving imaginary steam trains. Great!