New discovery reveals how the egg controls sperm entry

After the egg has been fertilized by a sperm, the surrounding egg coat tightens, mechanically preventing the entry of additional sperm and the ensuing death of the embryo. This is according to a new study led by researchers at Karolinska Institutet and published in the journal Cell. The work also explains how mutations in egg coat proteins can cause female infertility and may eventually lead to new contraceptive methods.