OKAY - We know that a Horcrux is made by the splitting of a soul through the murder of another person. We also know that Harry was inadvertently made into a Horcrux. So my question is...
Would it be possible that the creation of life (as in, Harry having children) be as soul-altering (changing, splitting, merging, what have you) as the murder of another? Would it be enough to, say, pass along a part of the piece of Voldemort's soul to his children (assuming Harry had children before Voldemort was destroyed)?
...Even if it's not quite canon, would it be a plausible plot line, or am I barking up the wrong tree completely?