"We stereotype men as aggressive and women as kind. When women violate those stereotypes, we judge them harshly. 'A man has to be Joe McCarthy to be called ruthless,' Marlo Thomas once lamented. 'All a woman has to do is put you on hold.' In one experiment, researchers asked people to read about a workplace conflict between two women, two men, or a man and a woman. The conflict was identical, but when the case study was between two women, the participants saw it as more damaging to the relationship and expected them to be more likely to quit. When men argue, it’s a healthy debate. When women argue … meow! It’s a catfight."
Write Sheryl Sandberg and Adam Grant in "Sheryl Sandberg on the Myth of the Catty Woman."
And I'll just add: Women co-authors aren't any more credit-demanding than men co-authors. It just looks better to have their name as part of the title.