As far as I know, we as humans share 99.9 similarity in our genomes. Further, we inherit 50% of the genome from our parents. So, it is correct to say that parent children have a 99.95% similarity in their genome?
The common wording is that the difference between two human haplotypes is 0.1%. This number only counts base substitutions, not insertions/deletions (indels) or structural variations (SVs). SVs together affects more bases than base substitutions. Also, the number is smaller is non-Africans (~0.07%) and higher in Africans (~0.12%). Anyway, let's denote this number by $\theta$, also known as the scaled mutation rate.
Because human is diploid, you need to count genotype differences when you compare two human individuals. Under the Wright-Fisher model, the rate of genotype difference on autosomes is
The rate between a child and his/her parent is, I think:
Note that I am sure the rate can be theoretically calculated but I am not confident in my calculation. Also, the rate of genotype difference on sex chromosomes or mitochondrial DNA is different.
The answer is no if the question is read at face value,
- I don't know the metric used (is this just SNPs?), nor which part of the genome is included in the calculation, just the exome?
- Moreover, if the genetic identity between parents is unknown, then the similarity of their offspring to either parent cannot be calculated.
- Your calculation excludes de novo mutations, particular at neutral sites and copy number variation, e.g. microsatellites, however its not clear whether the data is simply the exome.
- Homologous recombination is excluded, i.e. particularly occurring in the parental germ-line, there must be stochastic effects even in the first generation.
- Finally, mtDNA is maternally inherited.