c:\@Work\Perl\monks>perl -wMstrict -le
"use strict;
 use warnings;
 ;;
 use Data::Dump qw(dd);
 ;;
 my %son_father;
 ;;
 my $name1   = 'Jeff';
 my $add_dad = 'Doug';
 ;;
 $son_father{$name1} = {$add_dad};
 ;;
 dd \%son_father;
"
Odd number of elements in anonymous hash at -e line 1.
{ Jeff => { Doug => undef } }

##</code><code>##

while (1) {
    # display the menu
    print $menu, "\n\n";

    # get the user choice 
    print "Make your choice: ";
    chomp($choice = lc <STDIN>);

    # fulfill the user request 
    if ($choice eq 'a'){
        print "Enter a male name: ";
        chomp ($name1 = lc <STDIN>);
        }

    if (exists $son_father{$name1}) {
        print "Duplicate name -- try again!\n";
        } 
    else {
        print "Add a father: ";
        chomp ($add_dad = lc <STDIN>);
        $son_father{$name1} = {$add_dad}; 
        } 
        
    ...
    
    }  # end while loop