[1][2] Her mother, Marion Bidder, had been a pioneering woman student before teaching physiology and botany at Girton and Newnham colleges.
[3] Bidder was educated at the Perse School for Girls, and then went on to study Zoology for a year at University College, London.
[4] Her elder sister had chosen to study at Girton, the only other women's college in Cambridge at the time, and their mother wished to send one daughter to each.
In 1950 or 1951, she and two friends, Kathleen Wood-Legh and Margaret Braithwaite, formed the "Dining Group" for female academics in Cambridge who were not Fellows at colleges.
As well as social gatherings, they had the eventual aim of attracting a core of academics to establish a new female graduate college.