Fertility
From Tardis Wiki, the free Doctor Who reference
Male fertility in the Western world on an alternate Earth, according to a study done by the alternate Torchwood Institute, was linked to lifespan. (PROSE: Doctor Who: The Encyclopedia [+]Loading...["Doctor Who: The Encyclopedia (reference book)"], The Time Traveller's Almanac [+]Loading...["The Time Traveller's Almanac (reference book)"])
