Its the genetic health that's important, not the health health of the plant. But a healthy plant probably also has good genetics. Seeds have all the genetic characteristics of all their ancestors on both sides of the family carefully stored away. The farther from the ancestors you get, the more the plant changes because the plants blessed with good genetics are the ones most likey to survive and thrive and produce the next generation. And they won't be exactly like their parents. Close, but not quite.
If you want a plant to be exactly like its parent, then grow it from a cutting. A seed is going to change the genetics of the plant ever so slightly. We take advantage of that by selectively breeding for certain characteristics: size, vigor, color....
Daisy
