Try these parameter values:

All else being equal, an asexually reproducing population will grow at twice the rate as a sexually reproducing population. The reason for this is simple: members of a sexually reproducing population must produce both sexes, but effectively only half of them can "give birth" to offspring ot their own. In contrast, all offspring of an individual from an asexually reproducing population can potentially "give birth". This is the two-fold cost of sexual reproduction.

Despite this cost, sexual reproduction is a prevalent mode of reproduction. Therefore, there must be some advantage to reproducing sexually, or else the sexually reproducing populations would soon become replaced by the much larger sexual populations. One advantage of sexual reproduction is that sexual reproduciton maintains more genetic variation than asexual reproduciton.

Adjust the fecundity and initial population size of the two populations to the right:

Notice that even if the sexually reproducing population begins with twice as many individuals as the sexual population, the asexual individuals will shortly outnumber the sexual individuals (assuming equal fecundity).

If the fecundity is set to one for a population, the population size will not increase because each individual will only replace itself.