They were outspoken, confident and indifferent to the silent or explicit rules of gender around them, often dressing and acting “like boys.” They stood in stark contrast to the ingénues and highly feminine characters girls and women were often restricted to. For me and many Gen X girls (and boys), the tomboys of the 1970s and '80s expanded the possibilities of what girlhood could look like. I have met only one woman who liked Blair better than Jo.

These were often my favorite characters, living examples of the feminist zeitgeist that told me I did not have to be feminine to be female: I could, and maybe should, dress and act like boys and have access to their domains. In her book “Pink and Blue: Telling the Boys From the Girls in America,” the historian Jo B. Paoletti points to Sears catalogs in the 1970s that displayed size conversion charts so girls could shop more easily in the boys’ section. During that same period, Title IX mandated that girls have parity with boys in all aspects of federally funded education.

But this kind of tomboy began to recede in the mid-1980s. Hostility to feminism emerged in that decade, with the rise of the New Right. This was followed by the pink-hued “Girl Power” of the 1990s, which moved away from the more masculine-presenting tomboy toward an image that seemed to comfort the male gaze. Jo gave way to Sporty Spice, Xena, Buffy — coifed, petal-lipped and sometimes baring midriff — with the message that one didn’t need to sacrifice femininity to have power.

It was an understandable counter to the somewhat limiting message of the earlier tomboy era, which implied that while masculinity was good for boys and girls, femininity was bad for both. But it also edged out a certain kind of acceptable masculinity in young girls, and came with its own confinements — namely the idea that girls could be strong, so long as they were also pretty.