My understanding is that there is no reason to believe that homosexuality is not a choice. There is, however, evidence to support that there are relationship issues involved in causing this abnormal attraction to the same sex.

And then there is also God's clear Word that calls it an abomination. A person always has a choice whether or not to commit a sin. Whether the attraction is there or not, there is always a choice about acting on it.

There is also research that supports that a traditional marriage (one man and one woman) is the best option by far in raising children.