Caenorhabditis elegans primarily reproduces as a hermaphrodite. Independent gene conversion events in mutant obligately outcrossing populations of C. elegans [fog-2(lf)] spontaneously repaired the loss-of-function mutation in the fog-2 locus, thereby reestablishing hermaphroditism as the primary means of reproduction for the populations.

Why are we not hermaphrodites? This paper argues that while hermaphroditism is an efficient means by which genes may propagate themselves, inherent tendencies towards polygyny undermine its stability. Understanding the forces that have established a segregation of sex functions between male and female individuals provides insight into the concept of gender.

Until recently the determination of the sex of an individual was mainly based upon the gonadal structure, and the sexual individuality identified with this finding. Accordingly a person having testes was a man and one having ovaries a woman. In the hermaphrodites certain anomalies inside the genital tract were considered more or less as anatomical variations from the normal without more profoun...