Do hormone drugs affect whether a person feels sexual attraction to males or females?
There is no evidence that postnatal hormone exposure can change the sexual sexual preference of an individual. However atypical hormonal stimulation of the fetus can induce homosexuality.

Homosexuality does not develop without a variety of social factors which are up-to-date mostly unexplained. But can develop without hormonal stimulation.

As real life examples there are a androgen antagonists for the treatment of of prostate cancer, which reduce the testosterone level in males. Under treatment the men often turn softer and more emotional, as described by their wifes. And there is beer which contains oestrogens and can induce the growth of female breasts in men. But none of this mechanisms has been observed to turn males homosexual.



Further Reading (second text is free fulltext):

[1] http://www.ncbi.nlm.nih.gov/pubmed/23397798

[2] http://endo.endojournals.org/content/152/8/2937.long