Ersatz Culture has been systematically graphing all the awards (well, lots of them but maybe not all of them) in terms of gender and very systematically.
There are a host of different patterns in those graphs – note these are my observations not those of Ersatz Culture. Some awards are more volatile than others and, of course, some awards are very recent. Overall, there has been the shifted already noted from:
- Mainly men
- More men than women but many women
- Mainly women
The nearest graph to one that splits neatly into these phases is the Nebula Award for Short Story https://sf.ersatzculture.com/gender-award-charts/index-nebula-sfwa.html#nebula-award-short-story but as with any narrative overlaid on data, take it as the speculation it is.
There are few examples of an award bouncing around a 50/50 split. The Arthur C Clarke award though seems to have less of a trend and more of a noisy wobble around a 70/30ish split. https://sf.ersatzculture.com/gender-award-charts/index-british.html#arthur-c-clarke-award-best-science-fiction-novel
Young Adult awards have been more favourable to women. Fantasy awards have tended to be more favourable to women also. Any shift in a generic award towards YA or fantasy therefore might also lead to a shift towards women.
New writer awards (the former-Campbell Award, Locus Best First Novel) have often had a better split (not always a good split) than other awards in the same year. That is interesting as they might be a leading indicator of future award demographics in these awards.