If God intended marriage

Go to Individual Exercises at the end of Chapter 7 and evaluate Example 4, which begins “If God intended marriage...” Assume the premises are true. Applying only tests 2, 3, and 4 (logical strength, relevance and non-circularity), what condition of worthiness and reasonableness does this argument not meet? Explain your answer.

“If God intended marriage for the sole purpose of human reproduction, and if same-sex couples are entirely incapable of human reproduction, then it follows that God did not intend marriage for same- sex couples.”