All lives don't have equal current value, but the do have equal eventual value - I'll explain that in a moment (please note: I mean financial/economic value as I believe the term "moral/intrinsic" value to be so vague and undefined as to be completely useless as a thought model or reasoning tool - I understand what Melinda means).
This is empirically correct - a poor person in Africa is worth less than a rich American - by definition of earning capacity, consuming capacity, life expectancy and investment in their quality of life.
Please note: This does not mean the American is better than the African - it's merely an accident of birth.
Now here's the point I'm going to make.
Keeping people alive has exponential value - irrelevant of current value (e.g. African vs. American). What is the cost of keeping a poor African alive? I'm going to say for ~90% of the population it'll be around $1-4K a year. Now this is relatively expensive - however you must remember, this African will go on to consume and work all their lives, have kids who themselves will have kids and so forth - a combinatorial explosion of development and production making us all the richer.
Think of it like this: We are all descendant from a group of ~2000 people from Central Africa ~250,000 years ago. They produced ~7 billion people over the course of a few hundred thousand years - that's some seriously insane value generation right there. Imagine if we did the same with the ~7 billion we have now - we could be the ~2000 of the next millennium.
Each life you save today means hundreds or even thousands in the future - it's like an exponential investment. This is why we should protect poor people - apart from fuzzy moralistic reasons. It is a financially sound investment.
Each poor person will be an eventual consumer and producer - we must maximise their ability to do so - and that is why we must fundamentally help them. It also feels good.
This is what I find so toxic about the entire Republican/private health care in America debate. You invest millions over the course of people's lives to keep them alive (schools/roads/bridges/cheap loans/national security/etc.) and all of a sudden, if they get sick, you're happy that they metaphorically shoot themselves in the head because of their sickness (bankruptcy/can't afford/die etc.). Hence, you must also be happy when this kills the ability of their families to consume, produce and reproduce by an order of magnitude for the foreseeable future. We must keep people alive not merely because it's a good investment in aggregate, and not merely because it is the correct thing to do, but also because it's financially nonsensical to do otherwise - especially in a first world country. People are expensive, they take huge amounts of resources to bring up, and they have a high ROI - we should protect these investments for the sake of protecting our collective future.
Secondly, pushing birth control doesn't do jack to population growth. The vast majority of variance in development/population rates between countries is explained by GDP per capita. Or as Karan Singh, a former minister of population in India once stated:
> Development is the best contraceptive.
-- Source: http://en.wikipedia.org/wiki/Demographic-economic_paradox
Disclaimer:
Just to reiterate - I am not saying that one human is better than another in any sense of fundamental long-term value. I merely state that current value of any one human is grossly unequal due to path-dependent birth (born in America vs. Afghanistan) - however I mean to strongly imprint upon you that that the current value of a human doesn't matter in the long term - because humans in aggregate are worth the same over many generations because:
> In the long run we are all dead.
-- John Maynard Keynes
What matters is how we ensure the survival of a vibrant next generation, regardless of race, creed or birth.