A First Step Towards Eugenics?

I've posted stories before about incentive payments being used for various ends, such as to encourage patients to take medicine or to be good parents. Well, now it seems that a group in the US is paying drug users to get sterilised! I'm not sure I really agree that this is exploitative, whether or not I agree with it all things considered. What worries me is that it could be the first step towards more widespread eugenics, if other 'undesirable' groups were to start being paid not to breed...