Each woman is one less womb, one less mother, that many fewer children. Women of child-bearing age are the ultimate limited resource, the bottleneck.
Women and kids are why Horatius held the bridge - whatever the poem says about the ashes of his fathers and the temples of his Gods.
In the age of obsession over overpopulation, your womb theory is really obsolete.
You may be right, but we have arguments that are just as strong, and less controversial, than that one. The percentage of women who are drafted to serve in the military in any capacity who would not have to leave young children behind, who would report for duty, and who would not get pregnant within a year of boot camp would be very low. So, let's not start the whole mess.