Science has not determined the source, but it remains that the most accepted scientific theory is that sexual orientation is genetic.
What you describe is sexual behavior, which is not the same as sexual orientation. Example, heterosexuals who practice unsafe sex, are at a higher risk of getting sexually transmitted diseases, but that does not make heterosexuality immoral\bad, it simply means some who are heterosexual engage in sexual activities that are unhealthy. Same is true for everyone, irregardless of their sexual orientation.
Sexual orientation does not predetermine sexual behavior\choices