I think 11 is yes, if the parent is 40 and the child is 20. (and they had kids when they were young) 12 is yes, if the parent is 30 and the child is 10. 13 is yes, if the parent is 60 and the child is 40. unlikely though, but who cares. 14 is no, the parent would have been really young when they gave birth to the child. like 10.