AWKWARD ZOMBIE

Despite being one of the most central species in the Mario series, very little solid information has been provided on the unique reproductive biology of the Yoshis.

The in-game Japanese text of Yoshi's Trophy in Super Smash Bros. Melee states that Yoshis reproduce asexually, meaning that they reproduce without a mate and are neither male nor female. This is supported by the fact that in the Chef minigame in Game & Watch Galleries 2 and 4, after being fed long enough, the Yoshi produces an egg that eventually hatches into another Yoshi. The baby then takes its parent's place and proceeds to eat enough food to turn into an adult, eventually producing a fertile egg of its own, which then continues the cycle. This could be explained by parthenogenesis, which is when females of certain species have the ability to asexually produce offspring without the need of a male, however no official material has specifically named pathenogenesis as the asexual method that Yoshis use to reproduce.

Other sources have also contradicted the asexual depiction of Yoshis. At least one of the Yoshis in Paper Mario refers to his "son", and in Paper Mario: The Thousand-Year Door, the Yoshi who sometimes appears on-board the Excess Express expresses his hatred of business trips due to them keeping him away from his "lovely wife". The original Mario Party also features a pair of Yoshis which appear to be one male and one female, although the exact nature of their relationship was not revealed. Additionally, while Japanese language rarely involves gender-specific pronouns, the character Yoshi is consistently referred to with masculine pronouns in translation, yet laying eggs is one of his trademarks. This apparent contradiction was addressed in Super Smash Bros. Brawl, where Snake assumes that Yoshi is a female because of his egg-laying abilities, only to be corrected by Otacon (both of whom use "it" rather than "he" or "she" when referencing Yoshi). Since Yoshi's eggs have never been shown to hatch, it is possible that there are both males and females that lay eggs, but only the females' eggs have the ability to develop and hatch into a baby Yoshi, with or without the involvement of a male breeding partner.