It's easy to tick off a few tropes in Nintendo's core cast of characters. Mario, the everyman hero; Luigi, the trusty, goofy sidekick; Peach, the ever-present damsel in distress; Daisy, the strong, independent woman; Bower, the sociopathic villain; Wario, the crazy, get-rich-quick salesman; Yoshi, the not-a-care-in-the-world companion; the menial koopas, goombas, paratroopas, spinies, bullet bills, and other anthropomorphic creatures eagerly awaiting the footfall of the Mario Brothers' doc martens.
Then, sticking out like a sore, pink thumb, there's the male-to-female Birdo, begging for explanation.
The series explores the role Nintendo's censorship of certain titles played in shaping games in the 8 and 16-bit era, and how Birdo's outing via the Super Mario Bros. 2 instruction manual was really not the norm for the time. It's a fun read, despite the somewhat depressing subject matter, and well worth the time to read through all three parts. It's a bit of an overview into a subject that, sadly, hasn't made a lot of progress in the last 30 years, although things have noticeably brightened in the past few years. Really, the biggest piece of news for me in the article was that apparently Yoshi and Birdo have been in a relationship for a while now. That's a rule 34 I think I'll avoid, thanks, but more power to them!