def connect_individuals(pop):
    """
    Makes the connections in the genealogy from parents to children
    and vice versa.

    :param population: Set of individuals to connect
    :type population: IndividualContainer

    :rtype void:
    """
    for ind in pop.individuals:
        fam, _ = ind.label
        ind.father = pop[fam, ind.father] if ind.father != '0' else None
        ind.mother = pop[fam, ind.mother] if ind.mother != '0' else None
        ind.register_with_parents()
