I'm having a hard time understanding the rule against perpetuities. Every time I think I get it, I got a MBE practice question wrong, it's maddening! Okay, so the rule against perpetuities is life in being plus 21 years, right? So consider this one: a grantor executes and delivers a deed to his daughter conveying his ranch as follows: "To my daughter for life, but if my daughter dies survived by her husband and children, then to my daughter's husband for life, with the remainder in fee simple to my daughter's children; but if my daughter dies survived by her husband and no children, then to my son in fee simple." Okay? And BarBri's answer says that this does NOT violate the rule against perpetuities. A huge WTF to me, because I thought it *does* violate the rule. The way I see it, what if the daughter divorces her husband, and marries someone very young, who was NOT born at the time the deed was delivered? Then the life in being is the daughter, and the part that gives the deed to her husband for life obviously has a possibility of extending beyond 21 year?! Otherwise known as the "unborn widow problem." Okay, if any of you understand the rule against perpetuities, please explain to me why the above deed is NOT violative of the rule? Mere thanks would not suffice for anyone who could help me understand this stupid rule.