The impact of getting a definitive answer to this question will be catastrophic for the LGBTQ+ community. It is best to leave the question unanswered.
If scientists prove that people are born gay and can link the development of same-sex attraction to a specific gene or genetic mutation, it will open the door for one of two things. If we are born gay and it proves to be a hereditary gene, homophobic parents carrying a foetus that has the gene could prove to terminate the pregnancy rather than give birth to an LGBTQ+ child. This would only serve to further marginalize the LGBTQ+ community. Alternatively, if it is a genetic mutation that causes same-sex attraction, the public will begin to view the LGBTQ+ community as victims of a disease. Neither of these outcomes will have positive outcomes for LGBTQ+ individuals.
Understanding why people are gay could lead to improved attitudes towards LGBTQ+ citizens. It could also lead to further public scrutiny of those that hold homophobic views and an end to damaging gay conversion therapies. All of these would be good outcomes.
[P1] The answer to the question of whether or not people are born gay will only have negative outcomes for the LGBTQ+ community. [P2] We should not seek to answer the question.
Rejecting the premises
[Rejecting P1] There are several important positive outcomes that could come from getting an answer to the question.