Ethicist: Robert Gillette has argued that because a thorough knowledge of genetics would enable us to cure the over 3,000 inherited disorders that affect humanity, deciphering the human genetic code will certainly benefit humanity despite its enormous cost.
Conclusion (however)
Gillette's argument is not persuasive. (it's not clear that a thorough knowledge of genetics would certainly benefit humanity, just because it could cure diseases)
Evidence (because)
He fails to consider that such thorough knowledge of genetics might harm human beings more than it would benefit them.
Evaluate
Whenever we're doing a Main Conclusion question, we prime our brains before reading the paragraph with the prevailing tendencies on Main Conclusion questions:
Rather than put the Conclusion as the final claim, the conclusion on Main Conclusion questions is usually found earlier than the evidence. Typically, it's ... - the very first claim of the paragraph - it's rebutting some previous or external point of view that isn't the author's
In this paragraph we start with an external point of view, Gillette's.
Most of the time in LR and RC, after an author attributes a point of view to someone, she pivots away with a but / yet / however.
That pivot doesn't necessarily mean we're hearing a conclusion.
It could go: However, Conclusion. After all, Support.
But it could also go: However, Support. Thus, Conclusion
In this paragraph, the word because clearly indicates that the last idea is Support, so that makes "G's argument is not persuasive" our Conclusion.
F.A.B.S. = for, after all, because, since (the four Support indicators you should memorize)
Goal
Since this conclusion is using referential language, "Gillette's argument is not persuasive" we need to substitute-in the specific language being referred to.