gistfile1.java

class Family {
    Man husband;
    Woman wife;
    ChildrenCollection babies;

    public Family(Man husband, Woman wife) {
        this.husband = husband;
        this.wife = wife;
    }

    public void makeBaby() throws GenderNotSupportedException {
        if(husband.getGender() == wife.getGender()) {
            throw GenderNotSupportedException(
                "Operation is not permitted for gays and lesbians.");
        }
        Child baby = new Baby(husband, wife);
        babies.add(baby);
    }
}