Oestrogen has peaked and ovulation is imminent. Professor Evelyn Telfer from the University of Edinburgh discusses the formation and release of eggs, as well as key new research into whether women can make new eggs.

Credits: Presented by India Rakusen. Producer: Ellie Sans. Assistant Producer:Jorja McAndrew. Executive Producer: Suzy Grant. Original music composed and performed by Rebekah Reid. Sound design by Olga Reed.

Special thanks to all contributors and audio diarists.

A Listen production for BBC Radio 4 and BBC Sounds.