I was unable to find where this was answered in the article. It also reads like the author relied mostly on novels, movies, and such instead on a the interview.
Women spies have been around just as much, if not longer - Virginia Hall, Mata Hari, Jane Whorwood, Elizabeth Van Lew, Anne Dawson, Violette Szabo. Going even further back consider the Japanese kunoichi (sp?), Empress Wei of China had a whole cadre of female spies. There are plenty of evidence of female spies in Ancient Greece, and in the Roman empire. There are Biblical stories of female spies.
Indeed there are novels & movies that depict female spies in a sexual way (and just as many depicting men as simple fighting machines) but pretending that women where not allowed to be spies is a disservice to women.