The probabilities you give are true only if each gene has exactly two alleles and both are equally common in the population. This is a relatively rare situation. I don’t offhand remember the average number of alleles per gene, but I believe that the vast majority of genes have one allele which is overwhelmingly common (greater than 99% of people will have two copies) and a few alleles which are vanishingly rare, while a minority of genes have multiple alleles (in some cases hundreds) which vary substantially in frequency.
So for most of the offspring’s genes there would be two identical alleles in both cases, and for a minority of genes the uniparental offspring will have about a 1/2 chance of having two identical alleles (since the parent will most likely have two different alleles at these genes), while the normal bi-parental person will have a low probability (less than 1/2) of having two identical alleles at those genes.
This goes only for genes; non-gene DNA (which is most of the human genome) is much more variable.
As for who the parent of this child would be, I don’t think that’s really a problem.
Suppose a couple went to a fertility clinic for assistance in having a child. They could have a sperm donor, an egg donor, a surrogate mother to gestate the child, and various doctors doing various things.
So the genetic heritage of the child is irrelevant, gestating the child is irrelevant, poking the syringes in various places and carrying out the procedures is irrelevant. The sperm donor is not the parent, the egg donor is not the parent, the surrogate is not the parent, the doctor is not the parent, and in the case of a clone, the nuclear donor would not be the parent. The person or persons who asked for the child to be created are the parents. But of course, the parents could fulfil any of the above roles as well…one parent could be a sperm donor, or a nuclear donor, or an egg donor, or a surrogate womb, or even a medical technician.
And we have legal methods of terminating parental rights, in the best interests of the child. So crazy people who want to create clones in order to enslave them would be unfit parents, the clone is a child entitled to legal protection, not the personal property of the “creator” of the child.
And there’s nothing obligating a fertility clinic or a host mother to provide a child for a crazy person, the reality is that it probably wouldn’t get that far in all but a few cases. The spectre of enslaved human clones isn’t very worrisome, because most fertility technicians aren’t amoral psychopaths who will create slaves for money. And if you want a slave, why not just kidnap some child off the street to enslave, why go to the hideous expense of creating one in a lab?
I think this idea comes from popular misconceptions about cloning. The way it’s seen in the movies, you have a big vat of goo, you inject some things into it, and have a Jacob’s ladder and a van de Graff generator in the background, and a few days later, out crawls a fully-formed adult human. In which case, manufacturing slaves might be economical. Of course, the reality is nothing like that, as most folks on this board probably know, but a minor detail like that won’t interfere with the public consciousness.
And I just can’t understand why people would assume clones could be legally ruled slaves or property. We have the 13th and 14th Amendments to the constitution, slavery is illegal. Oh, they say, but powerful people will benefit, so the law will be interpreted to exclude clones.
The hell? If powerful people can subvert the justice system and make slavery legal again, then we’re facing a much more serious crisis than the enslavement of a few clones, we’re talking about the total collapse of human rights in general. We’ll all be too busy fighting off stormtroopers and eating rats to survive to worrry about the fate of a few clones, no matter how sad the fate of any one individual person might be.