In vitro fertilisation by Science3point0.com on Flickr.This image shows sperm and an egg (or ovum) at the moment of conception by in vitro fertilisation (IVF). The egg is surrounded by protective cumulus cells around the outside surface, coloured yellow. The sperm need to penetrate the membrane surrounding the egg, called the zona pellucida, if successful fertilisation is to occur. Light micrograph.

In vitro fertilisation by Science3point0.com on Flickr.

This image shows sperm and an egg (or ovum) at the moment of conception by in vitro fertilisation (IVF). The egg is surrounded by protective cumulus cells around the outside surface, coloured yellow. The sperm need to penetrate the membrane surrounding the egg, called the zona pellucida, if successful fertilisation is to occur. Light micrograph.

NIGHTNIGHT by DEDDY