Answer: The right answer is his own parents for having given birth to him.
Explanation: Just to elaborate a little on the answer, it can be added that the proud Doctor Faustus blames his horoscope as well as his parents for his terrible, yet expected, final: Mephistophilis has arrived and is ready to collect his soul, even though he deeply regrets having done what he has done - making a pact with the devil and giving up his soul. When talking about his soul, he exclaims: "But mine must live still to be plagu’d in hell / Curs’d be the parents that engender’d me! / No, Faustus, curse thyself, curse Lucifer [...]". A few lines before, he implores his stars to help him ascend to Heaven: "You stars that reign’d at my nativity / Whose influence hath allotted death and hell [...]." His time, nevertheless, is running out.