Sperm is generally frozen at minus 196 degrees Centigrade in nitrogen and can still be viable for many years. We have seen ten-year old sperm that is still viable. Their work is still somewhat new in evaluating chromosomal abnormalities. The more common way to examine abnormalities is to remove a cell from a growing embryo and evaluate it for a specific gene, etc. There are only a few labs doing this kind of work at this point.
Embryonic cells are totipotent in their early stages.
At this stage, they could theoretically split and form more than one individual. No one has done this on a practical level in humans. It has been done in the cattle industry, but in the human at this point, I am not aware of any programs doing this kind of work. We usually get about 10 eggs per retrieval, so something like this is not really needed from a practical standpoint. That is interesting and hard to answer.