Most sexually compatible organism

The organism with the greatest number of sexually compatible partners is the split gill mushroom (Schizophyllum commune), distributed in woodlands around the world, boasting an astonishing 23,000 mating types. In fungi, mating types are the equivalent of sexes in multicellular organisms and are thought to be the ancestor of distinct sexes.

In fungi, the genes that determine self-incompatibility divide populations into different mating types, and only individuals with different mating types can engage in sexual reproduction. In contrast, animals typically have only two distinct biological sexes, male and female. These sexes are defined by the presence of specific reproductive organs and, in many cases, differences in gametes (sperm and eggs).

Other members of the fungi kingdom with an astonishing number of mating types include the fairy inkcap mushrooms (Coprinellus disseminatus), with 143 mating types, each being able to reproduce with members of any of the other 142 types.