What is Sperm?
[[File:Sperm-egg.jpg|thumb|right|A sperm cell attempting to enter and merge with an egg.]] [[File:Espermatozoides.ogv|thumb|Swimming sperm]] '''Sperm''' are the [[male]] [[reproduction|reproductive]] [[cell]]s. Most [[animal]]s and [[plant]]s use sperm to reproduce. They have different ways of making and releasing the sperm. In all cases the sperm meets with the [[ovum|egg]] of the [[female]] and together they grow into a new organism. The name sperm is taken from the [[Greece|Greek]] word ''sperma'' meaning ''seed''.<ref>{{cite web|url=http://www.etymonline.com/index.php?term=sperm|title=Etymology of Sperm}}</ref> An animal sperm cell is capable of movement, as it has to get to the [[uterus]] to meet with the [[ovum]]. Animal sperm cells (including humans) have small 'head' and a long tail called a ''[[flagellum]]''. The flagellum acts like a [[motor]] to propel the sperm cell through the female [[reproductive system]]. == In humans == [[Human]] sperm is made in the [[testicle]]s of a [[man]]. Human sperm contains 23 [[chromosome]]s. A human needs 46 chromosomes, so a sperm cell is called a ''haploid'' as it only has half. The other half is contained within the [[ovum]] or egg of a female. During [[sexual intercourse|sex]], [[semen]] is shot out of the man's [[penis]] during [[ejaculation]]. Semen carries the sperm into the woman's [[vagina]] and down to the ovum in the [[uterus]]. During ejaculation millions of sperm cells are released in the semen, but only one hundred or so reach the egg.<ref name=analysis>{{cite web|url=http://www.questdiagnostics.com/kbase/topic/medtest/hw5612/results.htm|title=SemenAnalysis Male Fertility Test, Sperm Count|access-date=2008-08-30|archive-date=2008-08-28|archive-url=https://web.archive.org/web/20080828040822/http://www.questdiagnostics.com/kbase/topic/medtest/hw5612/results.htm|url-status=dead}}</ref> The egg can merge with one sperm cell that reaches it. Because it now has 46 chromosomes, it is called a ''diploid'', like ordinary cells of the body. This diploid is cal