As it is depicted in most textbooks, cross-over does not occur between the two "outer" sister chromatids. By independent assortment during Meiosis I, there is 1/2^23 chance that all father's chromosomes, with one pure father's chromatid, will end up in the same daughter cell. Does this mean that roughly one in eight million people does not have any genetic material from one of his grandparents or is there some more independent assortment during Meiosis II, which makes this outcome extremely unlikely? (more like 1/2^46)
More generally I would be interested in the probability that a gamete will contain more than 60% ,70%, 80% ... of only one of your parent's genes.