That's a common misunderstanding. First off, the people creating the babies have a moral obligation to ensure that there are enough resources to sustain their offspring.
Second, you're assuming that resources are static. If I devote some of my efforts to resource expansion (discovering new ways to grow food, discovering ways to reduce pollution, creating new medical services), then as long as I create more resource expansion than I'm consuming, my life is a net 'good' for those babies. In general, people devote more time to effective 'problem solving' when they're adults than when they're children. My attempts to expand the 'net resources' have been much more fruitful since I've become an adult.
As well, in life, every single act of consumption we perform negatively affects someone - someone who's alive NOW, not potentially alive later. Driving to work means the price of gas is a little bit higher, negatively affecting the people who need cheap fuel to live, negatively affecting the price of every good that requires transportation. However, we find this morally acceptable, as long as we don't overconsume, and as long as we contribute more than we take out.
I don't see why a potential life has a greater 'right to life' than someone who is alive now. Every time my girlfriend menstruates, we lose a 'potential life'. So what? It's a moral choice to not bring a being into existence when it cannot be afforded. However, my death would destroy a unique perspective on the world and a unique source of history regarding the world.