It’s said Fanny were the first all girl group to put out a record on a major label, but perhaps this ignores Motown (this song is a Marvin Gaye/Smokey Robinson cover)? This isn’t a racist conceit with two members of Fanny born in the Philippines.
So how about the band gets the kudos because they rocked to their own tunes that they also performed.
In 1970s larger society, women were becoming less deferential and advocating for equal treatment and respect. Fanny is said to have been a feminist beacon, at least for for rock music. They faced obstacles, even being prohibited from playing at a UK concert once for being too sexy!