It's hard to tell if this could be applied to your application, but the easiest way to deal with the circular references problem is to avoid it.

Instead of storing references to other objects within your objects, store your objects in an array, and then store indexes to the parent/child within the object.

package Family;

my @objs;

sub new {
   my( $parent, $child, %otherstuff ) = @_;
   push @objs, my $self = bless \%otherstuff, __PACKAGE__;
   $self->id( $#objs );
   $self->parent( $parent->id );
   $self->child( $child->id );
   return $self;
}
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It's one extra level of indirection, but no circular references.