It doesn't. In a species with 50/50 split between male and female, the number of males is almost irrelevant to population growth. Take rabbits. If you kill at birth 90% of the males, the population growth won't slow as the limit is the number of babies per-female. The 10% of males that survive simply father more kids via more females. Males can do that. Females cannot. Going one step further, killing all those males increases the resources available to the females. Ironically, culling those males can cause a population to grow faster than if they lived.