Study shows gender bias in science is real. Here’s why it matters.
blogs.scientificamerican.com
blogs.scientificamerican.com
This necessitates women either reducing their effort in grad-school or taking time off, whilst their career suffers. Of course some women do not have children, hence the comparison is useless, but in general society assumes women will have children and for a time be less productive.
Hence women get rated as less able to do work.
Political correctness is bullshit.
"When scientists judged the female applicants more harshly, they did not use sexist reasoning to do so. Instead, they drew upon ostensibly sound reasons to justify why they would not want to hire her: she is not competent enough."
Pregnancy was not used as an excuse. The other important thing to understand is why people pay so much attention to pregnancy but not to increased chances of having a heart attack or increased chances of alcoholism and drug addiction in men. Why are you going to choose only one difference between the sexes?