You think that finding one suitable partner isn't hard enough already? Joking aside - the complexity of getting 3 specimens of suitable sexes to produce offspring is probably what kills this possibility.
And the most benefit in terms of shuffling is between having recombination (sex) and not having it at all (cloning.) It is not evident to me that there's significant additional benefit from introducing the hypothetical 3rd sex.
And the most benefit in terms of shuffling is between having recombination (sex) and not having it at all (cloning.) It is not evident to me that there's significant additional benefit from introducing the hypothetical 3rd sex.