Which is ethically fine by me! I'm just pointing out that reproduction is one of the areas where the limitations of consent based bioethics are blindingly obvious.
The genes in sperm are physically different than those in eggs. It's called methylation and I gave you an example of a disease caused by it going wrong.
The genetic mix from parents is randomized. Always. Both good and bad results are equally the result of a random process initiated by the parents. A combination of recessive genes to cause disease is not more or less random than a combination of healthy genes. The parents roll the dice, the child gets the result.
In other words: The ethics can't proceed from first principles around consent to experimentation. It has to include, as you say, empirical questions about the technology in question. But that's a different sub-thread.
If I had to say anything about that: I think this is one of those things that is just going to happen whether or not anyone likes it. The fact that it has already succeeded with mice + the massive applications... it's just going to get tried, it's just a matter of which country it happens in. The fact that it could potentially be used by same sex couples is a total side note to how strongly this will be pulled along by the same existing demands that drive IVF currently, the potential is just too powerful. So I imagine we're just going to see eventually.
At some point you're going to want this if you're trying to pick specific genes from people or if you're doing things like making people with dozens of parents.