the basic problem is that, in the op's code, the object created by 'new child' simply has no information about any of the child's antecedents, only about the child. therefore, sending an object reference 'up' to person is pointless.

this seems like a good place to use a 'clone' object creation approach rather than a 'new' creation from scratch; each new object cloned from an old object can incorporate the information of the old object and add new information.

package Person;

sub create {

    my $class = shift;
    my $me    = shift;  # name of new being

    # should do some validation here

    return bless { me => $me } => $class;

    }

use constant ANON => Person->create('unknown');  # some folks have no 
+antecedents

sub bears {

    my $mom = shift;  # mother instance (matrilineal clone)
    my $me  = shift;  # kid's name
    my $dad = shift;  # father instance

    # should do some validation here

    return bless { me => $me,  mom => $mom,  dad => $dad } => ref $mom
+;

    }

sub ident {

    my $self = shift;

    return $self->{me};

    }

sub mom {

    my $self = shift;

    return exists $self->{mom} ? $self->{mom} : ANON;

    }

sub dad {

    my $self = shift;

    return exists $self->{dad} ? $self->{dad} : ANON;

    }


my $adam = Person->create('Adam');  # these folks are without antecede
+nts
my $eve  = Person->create('Eve' );

my $able = $eve->bears(Able => $adam);
my $mary = $eve->bears(Mary => $adam);
my $jane = $eve->bears(Jane => $adam);

print "first guy: @{[ $adam->ident ]} \n";
print "first guy's mom: @{[ $adam->mom->ident ]} \n";

print "Jane's mom: @{[ $jane->mom->ident ]} \n";
print "Jane's dad: @{[ $jane->dad->ident ]} \n";

my $fred = $mary->bears(Fred => $able);
my $jill = $jane->bears(Jill => $able);

print "Fred's dad: @{[ $fred->dad->ident ]} \n";
print "Fred's mom: @{[ $fred->mom->ident ]} \n";
print "Fred's dad's dad: @{[ $fred->dad->dad->ident ]} \n";
print "Fred's dad's mom: @{[ $fred->dad->mom->ident ]} \n";
print "Fred's mom's dad: @{[ $fred->mom->dad->ident ]} \n";
print "Fred's dad's dad's dad: @{[ $fred->dad->dad->dad->ident ]} \n";
print "Fred's dad's dad's dad's dad: @{[ $fred->dad->dad->dad->dad->id
+ent ]} \n";
print "Fred's dad's dad's dad's dad's dad: @{[ $fred->dad->dad->dad->d
+ad->dad->ident ]} \n";
print "Fred's dad's dad's mom's dad's dad's dad: @{[ $fred->dad->dad->
+mom->dad->dad->dad->ident ]} \n";

my $alan = $jill->bears(Alan => $adam);

print "Alan's dad: @{[ $alan->dad->ident ]} \n";
print "Alan's dad's dad: @{[ $alan->dad->dad->ident ]} \n";
print "Alan's mom: @{[ $alan->mom->ident ]} \n";
print "Alan's mom's dad: @{[ $alan->mom->dad->ident ]} \n";
print "Alan's mom's mom: @{[ $alan->mom->mom->ident ]} \n";
print "Alan's mom's mom's mom: @{[ $alan->mom->mom->mom->ident ]} \n";
[download]