Why Richard Dawkins tell Handicap theory unfounded theory

[Tae Jun, Yoon]

Let me introduce myself before I ask the theory.
I'm the undergraduate living in Korea. So this writing can be misunderstood. Sorry. (Though My english is poor, please reply this writing )

Lately, I read two books: "Selfish Genes by Richard Dawkins" and "Why is sex fun?-the evolution of human sexuality" by Jared Diamond.
In the Dawkins' book, he say "the handicap theory must be the unfounded theory. It can not be justified by mathematical genetics".
On the other hand, in the book by Jared Diamond, He justifies why the length of human sexual organs is longer than any other primates by The Handicap Theory.
Are the scholars still discussing this theory? Or Is there a certain proof that Dawkins' opinion-- It can't be justified by mathematics -- is right?

[Darby]

The theory is alive and well. I'm not sure what sort of confirmation Dawkins is looking for, exactly, but the underlying logic and confirming fieldwork is pretty supportive.