husband(arthur, beryl). father(arthur, carol). father(arthur, david). father(arthur, elaine). father(arthur, frank). female(beryl). female(carol). female(elaine). husband(frank, glenda). father(frank, linda). father(frank, malcolm). female(glenda). female(helen). husband(ian, natalie). father(ian, oscar). husband(john, katherine). father(john, glenda). father(john, helen). father(john, ian). female(katherine). female(linda). female(natalie). husband(paul, linda). father(paul, quentin). father(paul, robert). husband(stephen, carol). father(stephen, tom). father(stephen, ursula). father(stephen, violet). female(ursula). female(violet). husband(william, violet). father(william, xavier). female(yvonne). husband(zaccharia, yvonne). father(zaccharia, william).