From The Art and Popular Culture Encyclopedia
A spermatozoon (alternate spellings spermatozoan, spermatozoön; plural spermatozoa) is a motile sperm cell, or moving form of the haploid cell that is the male gamete. (A non-motile sperm cell is called a spermatium.) A spermatozoon joins an ovum to form a zygote. (A zygote is a single cell, with a complete set of chromosomes, that normally develops into an embryo.) The term spermatozoon comes from the ancient Greek word σπέρμα (seed) and Template:Unicode (living being).
Sperm cells contribute approximately half of the nuclear genetic information to the diploid offspring. In mammals, the sex of the offspring is determined by the sperm cell: a spermatozoon bearing a Y-chromosome will lead to a male (XY) offspring, while one bearing an X-chromosome will lead to a female (XX) offspring (the ovum always provides an X-chromosome). Sperm cells were first observed by Anton van Leeuwenhoek in 1677.