This paper makes a 0th order assumption that there is an inherent advantage to sexual vs asexual reproduction. There are certainly advantages to both, but the author is correct that the answer may come out of addressing complexity. Algorithmically, there are many approaches to modelling sexual selection (rather than natural selection). Sexual selection occurs much faster than natural selection and may be one of the reasons why we have such apparent gender differences within species. Describing the effect of complexity in terms of "fitness" is one of the largest challenges faced by computer scientists and biologists this century. If you are interested in exploring some different algorithmic models, "Computational Molecular Evolution" is an excellent book (http://www.amazon.com/Computational-Molecular-Evolution-Oxfo...).