Western women are already only producing ~1.5 kids (many with none!), you could send 50% of young women to die in war, then have the other half have a fertility

Western women are already only producing ~1.5 kids (many with none!), you could send 50% of young women to die in war, then have the other half have a fertility rate of 6, like what their great great grandmothers had, and we would be far far ahead already.