Re: It's attitudes like this that continue to perpetuate ignorance.
I can totally see how someone can make the correlation between homosexual behavior and raising kids outside of 'traditional' gender roles.
a. We grant them the assumption that being gay is a behavioral choice, because we don't want to insult their cherished beliefs.
b. Some closed minded people only understand being gay as assuming the opposite gender role as the one traditionally meant for that person. I.e. effeminate gay men, and masculine gay women. Clearly, they're not worldly enough to recognize the scores of 'manly' gay men, or 'feminine' gay women.
c. If people see doing effeminate or manly things as influencing the future behavior of said person, they jump to the conclusion that you can influence a child's eventual choice to be gay or not by confusing them with allowing behavior traditionally reserved for the opposite sex. One of the many reasons I find the Duggar show reprehensible.
Once you cease to grant them any assumptions without evidence, and don't give their beliefs, no matter how cherished, any undue respect when they don't comport with evidence it makes it harder for them to jump to such conclusions.