As the biological boundaries get pushed further and further and with no laws setting an age limit on IVF – how do we decide when someone is just too old to be a mum? We follow 60 year old Sue as she explores whether to have a second child to give her one year old a little brother or sister. Sue is just one of many women from around the world defying nature; there’s 70 year old Rajo in India and 64 year old Janise in America too – yet much of the public feels it is unfair on the children. But these women, who are old enough to be grandmothers, point out without them, those children wouldn’t exist otherwise.

Ground-breaking science, philosophical musings, divisive public opinion and deeply personal stories from across the world make for a unique insight into this modern day phenomenon.