If there is a choice, I think most of the parents don't want their children to be on a tough road ( like being single and childless for the entire life, dropping off Yale and starting their own small business, joining army, marrying a lower-class wife/husband, being left-handed or being gay.) However, unlike dropping off Yale or marrying a lower-class spouse, being gay or being left-handed is not a choice. Maybe someone can become left-handed by practising, or becoming gay for fun, but most of them don't. They are born this way. Life for gay is very tough. They need their parents' love and support. So if parents say, "I wish my child is not gay", that is not because they think being gay is sin, but they know being minority is very hard.