The bibliography you use depends in large part on where you want to align yourself politically.
The endless debate cycle between disaffected and disenfranchised libertarians covers the topic of human rights quite often. Most of us agree that the UN declaration is not a viable framework, because some of the enumerated rights imply that someone, somewhere, would necessarily be impressed into compulsory service to enforce them. For example, a right to adequate medical care implies that someone must become a physician and supply that care, possibly without pay. The right to food implies that someone must farm it, possibly without pay.
Even the experts can make mistakes.
So rather than read what others have said on the topic, it may be better for you to simply think it out for yourself and see what you come up with. Ideally, you will come up with a set of principles that are unambiguous, self-consistent, and able to serve as the foundation for a civilized society. It's much harder than it sounds. Good luck.
It is indeed very tricky, better men than me have argued back and forth:
http://plato.stanford.edu/entries/rights-human/
It seems that I'll have to agree with you and smtddr, then, that it is a right.
Once the child is born, it should be accorded all the human rights... and that's where we run into trouble.
Some interpretations of the "right to life" include the "right to survival",
http://www.hrea.org/index.php?base_id=159
I'm probably missing the right bibliography, if someone can point me to which books I should read, I would be very grateful :)