Sex Read. Sex. Sex. The male gamete (sperm) fertilizing the female gamete (ovum) The gametes produced by an organism determine its sex: males produce male gametes (spermatozoa, or sperm, in animals; pollen in plants) while females produce female gametes (ova, or egg cells); individual organisms which produce both male and female gametes are termed hermaphroditic.
Frequently, physical differences are associated with the different sexes of an organism; these sexual dimorphisms can reflect the different reproductive pressures the sexes experience. Evolution It is considered that sexual reproduction first appeared about a billion years ago, evolved within ancestral single-celled eukaryotes.[2] The reason for the initial evolution of sex, and the reason(s) it has survived to the present, are still matters of debate. Some of the many plausible theories include: that sex creates variation among offspring, sex helps in the spread of advantageous traits, and that sex helps in the removal of disadvantageous traits.
Sex Disease. Safe Sex. Sex Positions. Young Man. Male Sex. Female Sex. Sex Appeal.