I got these figures from studies here in sweden where children have been DNA tested. (not for parenthood specifically) Still, one shouldn't put too much trust in these figures since these are from small sample studies.
But most people (perhaps my own prejudice beliefs?) drawing family charts do so to show ancestry with "nobler blood". Given the uncertainty mentioned above, this is complete and utter nonsense. You might be able to say with 75% confidence interval I am related to this or that person....But that really doesn't sound as cool, does it? 😉
I personally see the parents as the ones that actually raised you, not the donors. However, it becomes a bit absurd to claim that XX was my great great great great grand father, due to the uncertainty and the fact you or any one you know most likely haven't had any personal relation with this person.