In the In Her Name series by Michael Hicks, the Kreelans are cursed so that:
- Males are only used for breeding and then die after they've been "used" once
- Fertile females have to breed every few cycles (years) or they will die
This curse was inflicted approximately 100,000 years ago. At the time of the curse the Kreelans occupied their home world and a few small settlements on other planets.
In the subsequent 100,000 years the race grew to occupy a huge number of planets across the galaxy.
Given that of all the births mentioned in the series, there's no mention (as far as I remember) of multiple children (twins, triplets etc), but several mentions of single children, we can assume that multiple births are as common/rare as in humans.
How is it possible that the Kreelan race grew, given the curse?
Given that for every conception, a male of the species dies; surely it's impossible for the race to grow. Even if nearly all children were male (which they're not), they'd just stay at a level population, as for every birth there's a death...