They discuss this is in the article, but the most challenging part is dealing with imprinting in egg/egg fusion. Certain genes are deactivated in the testes and ovaries - so that effectively only one parent passes os certain genes. This is the body's natural defense against parthenogenesis (because it tends to represent a child produced by the mother alone in nature, which is evolutionarily very disadventageous).The future question is a fun one.
I would go with
Assuming viable embryos are not a rare commodity wherever you are at, or you are in a location where for religious/cultural reasons it is the case, then I don't see why it would be.
Probably a shift as things go from possible, slightly risky and expensive through to not only possible but less risky than biological and finally "it is odd that you would even consider naturally". Main modifiers being where robots capable of raising children are at and how far along into the post scarcity thing were are at, possibly also serious life extension but that starts going way off into science fiction for this particular discussion.
I don't think I can get to disingenuous, if nothing else "why don't we investigate every miscarriage as a potential murder?" comes into play.
Equally "Neither a sperm cell nor an egg alone" then technically two eggs can merge into one and has been the case for a while http://news.bbc.co.uk/1/hi/health/1431489.stm
We have to solve imprinting before we can start producing two egg embryos, but I don't think this is too far off. We somehow just need to demethylate the certain silenced genes. Funny thing is essentially you would still have to choose which mom is the "dad" to modify one of these eggs