Scientists have created sperm and have used the sperm to impregnate a mouse.
http://story.news.yahoo.com/news?tmpl=story&cid=1894&e=2&u=/ap/20031210/ap_on_sc/stem_cells_sperm
http://story.news.yahoo.com/news?tmpl=story&cid=1894&e=2&u=/ap/20031210/ap_on_sc/stem_cells_sperm
