wealth is relative, poverty isn't. poverty by definition means you don't have enough income for the bare essentials such as food and shelter.
look, you can see it's discriminatory to say it but the bulk of crime (especially the kind involving weapons and that gets people killed) and terrorism do stem from poverty.
it's human psychology demonstrated best by ....
http://en.wikipedia.org/wiki/Maslow%27s_hierarchy_of_needs
middle class and richer people are far more likely to have the bottom two needs met, and are usually more likely to have the other needs met too.
also consider that this would eliminate unplanned pregnancies, and thus essentially ensure that most kids are born into stable loving homes (those are who want kids and can afford to pay for art. inseminateion.)
forced slavery is more rampant now than it was at any other time in history, and it stems from the extreme impoverishment of certain parts of the world. the same with genocide etc. etc. and even war for the most part. a big chunk of the world is currently in the middle of conflict. yet the only one we hear about is iraq. why? because the other parts involve two really poor groups fighting and the west couldn't care less about that.
if you consider all the facts, this really is the only humane thing to do- tongue in cheek.