Persistent female choice for particular male trait values should erode genetic variance in male traits and thereby remove the benefits of choice, yet choice persists. One potential resolution to the lek paradox is Rowe and Houle’s theory of condition-dependent expression of male sexually selected traits. Similar to the handicap principle, Rowe and Houle argue that sexually selected traits depend on physical condition. Condition, in turn, summarizes a large number of genetic loci, including those involved in metabolism, muscular mass, nutrition, etc. Rowe and Houle claim that condition dependence maintains genetic variation in the face of persistent female choice, as the male trait is correlated with abundant genetic variation in condition . This is also called the "genic capture" hypothesis. The Hamilton and Zuk model addresses the lek paradox, arguing that the cycles of co-adaptation between host and parasite resist a stable equilibrium point. Hosts continue to evolve resistance to parasites and parasites continue to bypass resistant mechanisms, continuously generating genetic variation. The "worst-elimination hyp." suggests that only the worst individuals in the population should be eliminated by natural/sexual selection at each season, thus maintaining a large genetic variance in the population. Furthermore, females may be constrained in their directional choice for best partners by the rarity of these latter individuals and by sexual coercion. Thus a lot of "ordinary" individuals, not only the best, may pass their genes to the next generations and this may contribute to maintain genetic variability in the population.