Men were more likely to use words such as 'father', 'dad' and 'son', while women used 'mother', 'mom' and 'daughter'. And it was checked that writers were referring to their family most of the time, not themselves.
Similarly, studies suggest parents often feel closer to children of the same sex - most likely because they spend more time with them.
But Robin Lakoff, professor emeritus of linguistics at the University of California, told the New York Times that attitudes were changing:
Back in the 50s, men could show anger, rivalry and hostility, so they could swear.
Women could show fear, sorrow and love, and so they could cry.
But she said today it's a different story:
It’s probably best to say we are somewhat confused about gender roles and stereotypes.