The 70% statistic is very prominent, but some of my Iranian friends were incredulous of it. Some speculate that men tend to pick up skills during mandatory military service, so women make up a larger proportion of college graduates. Interestingly when you look for statistics on the workforce itself (rather than graduates with STEM degrees), you see familiar ratios of ~20-25%. E.g. https://www.tehrantimes.com/news/425963/23-percent-of-mobile...

"Women make up 48 percent of internet users, 45 percent of cellphone users, and 23 percent of mobile app developers in Iran, Telecommunications Minister Mohammad Javad Azari Jahromi said here on Sunday."

I can't seem to find stats on the aggregate gender breakdown of software developers in Iran.