One has to allow for a lot of factors in analysing that massive discrepancy. Firstly, women in Science were very rare for a long time. Secondly, even the ones who did make it were often somewhat looked down on by their colleagues (not always, but certainly officially they would often find it difficult).
A lot of this has changed now, but then thirdly: Nobel prizes tend to have a bit of lag before they are awarded for work from a long time ago, eg Peter Higgs and Francois Englert won their awards for work done during the 1960s. That lag affects everyone but then women in science in the 1960s were also rare. Fourthly, the awards committee has traditionally shown a bias in favour of the people who were officially in charge of the work, even if they didn't actually do the work itself. This hit Jocelyn Bell Burnell, but has affected plenty of other men as well who missed out in favour of their more senior collaborators. There have been various other controversies in the history of the prize, eg the 1923 prize for work on insulin that went to the head of the lab where the work was done, John McLeod, while (some of) the people who did the work were omitted (Charles Best and James Collip).
Essentially Jocelyn Bell was the victim of bias against PhD students, rather than a bias against women necessarily, and the whole picture demonstrates the historical difficulty women have had in being able to progress very far in science. It's unlikely that the balance between male and female winners of the Nobel Prize will ever be perfectly redressed, although in future you'd expect the ratio of men: women winning the prize to tend towards 1:1. But then it shouldn't be artificially redressed. I significant contribution to science should be the only criterion for winning the award.