"I'd like to know what law is it that says that a woman is a better parent, simply by virtue of her sex"

This quote by Robert Benton is a challenge to the concept that women are inherently much better parents than males. He is questioning the concept that a woman's gender alone makes her a much better moms and dad than a male. He is implying that there is no law or guideline that states this, and that it is a false presumption. He is suggesting that parenting skills are not determined by gender, but rather by the person's ability to nurture and take care of their children. He is likewise suggesting that both men and women can be similarly capable moms and dads, and that gender must not be the deciding factor in determining who is the better moms and dad. Eventually, Benton is challenging the idea that women are better moms and dads just due to the fact that of their gender, and is recommending that parenting skills should be judged on a specific basis.