We can go around hand-waving and saying how irresponsible people are, or we can recognize how people are, were and will be and make sure they don't accidentally reproduce for no good reason.
We know how, we just need to stop expecting people to be other than they already are for a minute and start a world-wide free-condoms campaign. Where's Bill Gates, make it happen! :)
Because you know who's supporting that single mother and all the difficulty that ensues? You and I, with our tax dollars and otherwise.
That is the problem that condom availability will not fix. The only system solutions are pushing girls into sports and other extra curricular activities, and getting more male teachers in elementary schools to provide proper role models. I'm well away from my desk so I don't have the study references, but both help in this regard.
And let's not forget the machines in a huge number of gas station rest rooms across the country. Most of them are $0.75.
If a person cannot find free or ultra-cheap condoms today, the person really is not trying and probably should be doing other things.
Also, as many of the folks at work discovered, the free contraceptives were accompanied with a larger than cost increase in premiums.