harry, for your podcast, you have taken a fascinating look at age difference in relationships. and the conceptions that have existed in our society for generations. what has been that conception for a long time. >> okay, over the last 25 years this -- there has been this quote/unquote rule to be socially acceptable. it is a statistical equation. your take the older partner's age, you divide it by two and add seven, that should be less than or equal to the younger partner's age. this say rule of thumb, not scientifically proven. what it suggests is that relationships should have smaller age gaps and age gaps become more acceptable the older you get. >> show me an example of this rule in action. >> yeah, why don't we use harry's parents at their time of their marriage. so what you do is take the 7, add the older partner's age, my dad was 57, divide by 2, you get 35.5. that was less than the younger