Question: If you could 3xtr4ct stem cells from a sp3rm, how much would it take to make a human sized stem cell?

Matthew Tomlinson answered on 25 Nov 2013:

Well a sperm is only one cell, and it only has half the DNA of a normal cell, just like the female egg cell. This is so that when the sperm and egg fuse the resulting cell has the correct number of chromosomes. This fertilised egg is one cell and is a stem cell because every cell in the body comes from it. So to answer your question you need one sperm cell (plus an egg cell) to make a stem cell.