If someone ever asks, why have more children if there's a chance they won't be normal, try out this Sarah Palin statement (Don't get excited. It's not political.) :
Normal? Look around. What's normal?
(She answered something pretty close to this when asked about her cutie pie son with Down Syndrome. I did not put it in quotes because I can't remember the particulars.)
I asked my husband to weigh in with his suggestion of a pithy answer and the first thing he did was to make a face. Not eye-rolling ; that's my talent. Sort of a wince with a half-shake. Anyway. Then he said (And I do quote), "Plenty of people with high IQs and perfect health are criminals." To which I would add ~ high IQs and perfect health are not exclusive conditions for a worthy, "normal" life. The old Baltimore Catechism for children asks this, "Why did God make us?" And the answer it gives is, "God made us to show forth His goodness and to share with us His everlasting happiness in heaven." Let's not be too hyper-spiritual here ; let's be honest, for this statement is wide open. It doesn't mention how life can be painful, sorrowful, depressing, and difficult ; but there is also room for wisdom, love, peace, and kindness. The everlasting happiness part comes in heaven, true, but there is certainly some here, as well.
We are Star Wars fans here and a line from one of the books (Did you know there were books? Better than the movies, of course!) has Anakin/Vader saying to his son as he lay dying in Luke's arms, "Luminous beings we are, Luke, not just this crude matter." Made in the image of God, we are body, mind, soul. Luminous. Normal.