#Main
my @whole_world = ();
my $misfits = {};   # the reference

foreach my $individual (@whole_world) {
    ($ok_ones, $misfits) = find_misfits(\@whole_world, $misfits);
}

print_misfits($misfits);

# sub
sub find_misfits {
    my ($whole_world, $misfits) = @_;

    my %candidates = ();

    # do stuff to find the misfits, ie compare the genetic setup of individuals

    # add individuals that don't fit to $misfits
    	$misfits{$stand}{$mother}{$offspring} = {%{$candidate{$stand}{$mother}{$offspring}}};

    return ($misfits, some more structures);
}