I have, however, found some startling figures on gender and membership in the Science Fiction Writers of America (SFWA) organization over the past 66 years. I'm not going to draw out any implications from these figures, but rather simply present them so that anyone who needs a quick reference can find them in one place (rather than hunt them down as I did).
Percentage of Female Members of the SFWA (1974-2015)
- In 1974, 18% of SFWA members estimated to be female*
- In 1999, 36% of SFWA members were female.*
- In 2015, 46% of SFWA members are female.**
- 47% male
- 46% female
- 7% "unspecified"
*Source: Davin, Eric Leif (2006). Partners in Wonder: Women And the Birth of Science Fiction, 1926-1965. Lanham, MD: Lexington Books. p. 69–70.
**Source: SFWA President Steven Gould (via twitter).