// if the number of individuals in this species is only
// one then we can only clone and perhaps mutate, otherwise use
// the crossover probability to determine if we are to use
// sexual reproduction.
if (opp.parentsNeeded() > 1) {
int numAttempts = 5;
this.parents[1] = chooseParent();
while (this.parents[0] == this.parents[1]