NEW YORK — In the opening pages of ‘‘The Feminine Mystique,’’ Betty Friedan consciously captured the despair of so many housewives — and unknowingly anticipated a shift in language that would mirror the revolution to come in women’s lives.

‘‘As she made the beds, shopped for groceries, matched slipcover material, ate peanut butter sandwiches with her children, chauffeured Cub Scouts and Brownies, lay beside her husband at night,’’ Friedan wrote in her 1963 book, ‘‘she was afraid to ask even of herself the silent question — ‘Is this all?’’ ’

The average reader might catch such ‘‘Mad Men’’ details as ‘‘matched slipcover material.’’ But a linguist or psychologist will be keeping score: ‘‘She’’ and ‘‘her’’ each are used twice; ‘‘herself’’ once. Not a single ‘‘he,’’ his’’ or ‘‘himself’’ appears.

The golden age of the male pronoun was ending.

According to a study released Thursday, the ‘‘he-she’’ gap in books — one that has always favored the masculine — has dramatically narrowed since the release of Friedan’s feminist classic.

Drawing on nearly 1.2 million texts in the Google Books archive, three university researchers tracked gender pronouns from 1900 to 2008. The ratio of male to female pronouns was roughly 3.5-to-1 until 1950, when the gap began to widen as more women stayed home after World War II, and peaked at around 4.5-to-1 in the mid-1960s. The ratio had shrunk to 3-to-1 by 1975, and less than 2-to-1 by 2005.

‘‘These trends in language quantify one of the largest, and most rapid, cultural changes ever observed: The incredible increase in women’s status since the late 1960s in the US,’’ Jean M. Twenge, a psychology professor at San Diego State University and author of ‘‘Generation Me,’’ said in a statement.

‘‘Those numbers are quite staggering,’’ says James W. Pennebaker, author of ‘‘The Secret Life of Pronouns’’ and chair of the psychology department at the University of Texas in Austin.

‘‘Pronouns are a sign of people paying attention and as women become more present in the workforce, in the media, and life in general, people are referring to them more.’’

In an interview, Twenge said that she and her fellow scholars — W. Keith Campbell, who heads the psychology department at the University of Georgia; and one of his students, Brittany Gentile — had been talking about the Google database as a resource for studying gender. They liked the idea of starting at 1900, because pronouns have not changed since ‘‘thee’’ and ‘‘thou’’ fell out of style in the 1800s.

Google offers much more information than what was immediately available just a few years ago, Twenge notes, although the material is far from complete; the search engine’s archive contains just 4 percent of all books published in the United States since 1800. But Twenge and her colleagues concluded that gender was not a factor in which books Google included.

‘‘You have this huge sample, with no biases,’’ Twenge says. ‘‘And you have an agreed-upon set of words.’’

‘‘It seems very comprehensive and well done,’’ Pennebaker says.

‘‘There are two types of data, imperfect data and no data. If you’re going to wait around for perfect data, you are going to wait around forever.’’

The new study confirms women’s great advances in education and in their success in getting published, says Erin Belieu, an award-winning poet and co-director of VIDA: Women in Literary Arts, a nonprofit organization founded in 2009.

‘‘Women have certainly increased their ‘literary output’ in the last two decades particularly,’’ she wrote in an e-mail.