With regards to the "sexual selection and genetic diversity" discussion, the basics of my point can actually be found on wikipaedia.
http://en.wikipedia.org/wiki/Chromosomal_crossoverThe process of crossovers leads not only to variations in which allele is given to one's offspring, but the process also allows for higher mutation rates.
More detail and better explanation of the situation.
http://www.biologie.uni-hamburg.de/b-online/e11/11d.htmThe professor who is arguing that our current scientific consensus might be wrong (with well reasoned arguments) has his own page at
http://www.carleton.ca/biology/people/gorelick.html