I might add that the conversations need to be different and filtered according to your differences... For instance, The older person should not tell the child what is happening in his marriage and how their sex life is going... Instead he should model his situation into a desirable one for the child and be a role model... Such as speaking highly of his wife, and giving insight for the child to find a great wife as well (if not better)...
Like wise a male female relationship should filter some topics with the upmost regard... And try to perpetuate the best of their gender that they have to offer, as a hope for one and other... And encouragement.