Let's speculate about Pinkie Pie's gender identity.

C. R. Ravenswood

I think her gender is “pink”.

witchy witchy Opalicchi

creatures with Pink gender:

Pinkie Pie
Chihaya Anon
Renako from Watanare
Elita-1 from the Transformers franchise

Imicow

Kanae from Teekyu (covert but pink)

chiralica

Poppy Pipopapo