Canonical genetic algorithm - Mating:

In such a scenario this continues until the number of offspring that is produced is the required number. Further this required number is the same as the current population size and to keep the population size constant. Hence notice that there are repeated individuals in the IP, thus some individuals may become the proud parent of multiple children. 

However this mating process has some anology regarding with natural evolution this means sometimes the fittest organisms may not have the opportunity to find a mate plus whether they do find a mate, it's not guaranteed, they will be able to reproduce. Moreover the analogy regarding to natural evolution also breaks down here just because individuals can mate with themselves and there is no notion of sexes.