Sperm Use Heat Sensors to Find the Egg

Much like guided missiles that sense the heat of a plane?s engine, sperm are guided to the fertilization site by temperature, reports a study published in the current issue of Nature Medicine. The site where the egg lies is slightly warmer than the place where the sperm make a pause in their journey through the female genital tract. Sperm cells are apparently guided by this temperature difference in their navigation. Such a temperature-driven mechanism was previously known to exist in microorganisms and worms, but the Weizmann study for the first time has provided evidence for its existence in sperm cells.