spe-27 encodes a novel, hydrophilic protein; spe-27 is required for hermaphrodite spermatogenesis or sperm activation but not for male-derived sperm activation (sperm activation is the morphogenesis of a round non-motile spermatid to an amoeboid crawling sperm); however, mutant hermaphrodite spe-27 spermatids can transactivate and form functional sperm during mating with males; genetic and phenotypic evidence suggests that spe-27 acts in a common pathway with spe-8, spe-12, spe-19 and spe-29.