Here is my argument: There is not conclusive proof that there is a biological basis for homosexuality in humans.
Another argument: Romans 1:16-32
16For I am not ashamed of the gospel of Christ: for it is the power of God unto salvation to every one that believeth; to the Jew first, and also to the Greek.
17For therein is the righteousness of God revealed from faith to faith: as it is written, The just shall live by faith.
18For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of men, who hold the truth in unrighteousness;
19Because that which may be known of God is manifest in them; for God hath shewed it unto them.
20For the invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead; so that they are without excuse:
21Because that, when they knew God, they glorified him not as God, neither were thankful; but became vain in their imaginations, and their foolish heart was darkened.
22Professing themselves to be wise, they became fools,
23And changed the glory of the uncorruptible God into an image made like to corruptible man, and to birds, and fourfooted beasts, and creeping things.
24Wherefore God also gave them up to uncleanness through the lusts of their own hearts, to dishonour their own bodies between themselves:
25Who changed the truth of God into a lie, and worshipped and served the creature more than the Creator, who is blessed for ever. Amen.
26For this cause God gave them up unto vile affections: for even their women did change the natural use into that which is against nature:
27And likewise also the men, leaving the natural use of the woman, burned in their lust one toward another; men with men working that which is unseemly, and receiving in themselves that recompence of their error which was meet.
28And even as they did not like to retain God in their knowledge, God gave them over to a reprobate mind, to do those things which are not convenient;
29Being filled with all unrighteousness, fornication, wickedness, covetousness, maliciousness; full of envy, murder, debate, deceit, malignity; whisperers,
30Backbiters, haters of God, despiteful, proud, boasters, inventors of evil things, disobedient to parents,
31Without understanding, covenantbreakers, without natural affection, implacable, unmerciful:
32Who knowing the judgment of God, that they which commit such things are worthy of death, not only do the same, but have pleasure in them that do them.