In a breakthrough in fertilization research, scientists identify the surface proteins that enable a sperm cell and egg cell to fuse together to form an embryo.
Juno is the name given to the egg's protein and Izumo the sperm's.
Researchers are now screening infertile women to determine if the absence of Juno is the problem. Twenty percent of infertility cases are of unknown origin.
If the absence of Juno is, indeed, the cause of infertility then a simple diagnostic test can be developed to identify affected women.
A woman's Juno status will also guide fertility treatment by allowing in vitro fertilization specialists to proceed directly to intracytoplasmic sperm injection.
Researches identified Izumo in 2005 but couldn't identify Juno until recently.