Sperm bank. Laboratory worker placing a sperm sample in a centrifuge. The sperm is liquified, filtered and centrifuged, causing the seminal plasma to separate from the sperm cells. This work is being carried out at Cryos International Sperm Bank, Aarhus, Denmark. The world’s largest sperm bank, it has stocks of over 170 litres of sperm (around 130,000 samples) that are used for fertility treatments, creating more than 2000 babies each year. Photographed in 2012.