What if that sexual partner you'd rather forget remained forever a part of your life?

Sydney scientists have shown for the first time that offspring can resemble their mother's previous sexual partner – in flies, at least.

Fly offspring can resemble their mothers' previous partner.

The research team, led by evolutionary ecologist Angela Crean, propose that sperm from a previous partner can penetrate a developing egg, influencing its growth despite being sired by another male.

Dr Crean said her team were shocked when their experiments revealed they had discovered a new form of non-genetic inheritance.