Now days one can clone or have many genetics. Other than that, they even find that baby's genetics can get in mother. I gues think of it as you can get blood transfer and some cell get transfered beyond blood. They just found that in dogs, older sibling's genes can pass to younger. There are people with dual genetics (like conjoining twin without extra limbs).
So anyway, there are egg with 23 chromozome plus other rna etc. sperm have 23 chromozome. Sperm can be replaced with another egg. Or technically I think any of 46 can be replaced etc. Plus people can have multiple genetics( as in blood transfusion or function like organ transplants but at cellular level).