This ad is for Artificial Insemination, for egg donors. And it completely annoys me whenever I see it, because it’s wrong, all wrong. Not because the idea is wrong, but the maths is.
(if you haven’t studied basic inheritance, a child gets half of its chromosomes ie genes from each parent. So a child only ever has 50% of the two biological parent’s genes. So when you use donor genetic material, replacing one part of a couple’s contribution, the child will only have 25% of their genes)
Sorry your reasoning seems to be in error. Children get 50% of their chromosomes from their mother and 50% from their father. If it was 25% from each, where does the missing 50% come from? Therefore with the father being both the paternal and biological parent, the child will have 50% of his genetics, although not the mother’s.
Each parent has 2 sets of chromosomes, so there’s a total of 4 sets of chromosomes between them. The child has 2 sets, one from each parent, so has 50% of their chromosomes. So the child does get 50% of its genes from biological parents, but out of the total genetic material available between the parents, only has half.
With AI, only 1 set of the child’s chromosomes is from the parents, with parents here being the couple who will raise the child, not the two people who contributed to the genome. So the child only has 1/4 of the parents chromosomes, 25%.