I mean, sure. We need more research. But shouldn't the null hypothesis be that children born of a novel and extraordinarily unnatural process be less healthy than those born of the usual process?
There's no reason to believe that after all the factors arrayed against IVF children (poor starting egg quality, genetic and cellular damage from ice crystals, mitochondrial damage potential, implantation problems, etc) that the null hypothesis would be "they will be exactly the same".
> (poor starting egg quality, genetic and cellular damage from ice crystals, mitochondrial damage potential, implantation problems, etc)
Well, IVF doesn't necessarily imply any of those things -- in male infertility the eggs may be of high quality, in a fresh cycle the embryos may not be frozen at all, in a healthy mother there may be no implantation issues, etc. There are perhaps hundreds of factors to control for, and the null hypothesis would change depending on the population of IVF children (and their parental history) you're studying.
There's no reason to believe that after all the factors arrayed against IVF children (poor starting egg quality, genetic and cellular damage from ice crystals, mitochondrial damage potential, implantation problems, etc) that the null hypothesis would be "they will be exactly the same".