Earlier quoted context omitted.
But you're making assumptions and predictions based on nothing. If someone leaves, they leave. If they come back, they come back. Male or female. Makes no difference. You can't control it. You can't predict it. You imagine a level of control that you simply don't have. Conversely, there is a net benefit to society that simply cannot be ignored. It's life.
The approach blucalm is offering is nearly the definition of sex discrimination. You can’t play the odds when hiring in protected classes, you need to assess the applicants on an individual basis...
Except that he probably cannot (for example) ask the applicant if they are likely to have kids or use the leave policy in the near future. That would be judging them on an individual basis, but in many jurisdictions it's prohibited.