Two crosses were assembled in separate cages. Each cage contained 100 wild-type virgin females, 100 wild-type competitor males, and 100 DSX males that were either raised normally (non-sorted DSX males) or sorted three times with the COPAS (sorted DSX males). Freshly emerged mosquitoes of each kind were simultaneously placed in the cages and kept together through the blood meal on day 5 until day 8, when females were isolated into single plastic tubes to oviposit on shallow water. Freshly hatched larvae were examined under the fluorescence microscope to score the identity of their father (100% fluorescent progeny indicated a DSX male, 100% non-fluorescent a competitor male, mixed progenies arose from females fertilized by at least two males of different genotypes). Results from the two crosses are not statistically different (χ2 = 1.053, p = 0.5906). Several repeats of this experiment confirmed that COPAS-sorted males are not noticeably inferior in their reproductive competitiveness.