I found Rick Hess's "humor" to be a bit hostile and sexist in places (such as on page 88 when he implies men would rather kill themselves than let their wives manage their homes.) It distracted from what is a serious subject.
The probability chapter struck me as being quite irrational. Mr. Hess's states that there is no such thing as probability, that we are denying God's sovereignty, when we believe that 2 parents with blue-eyes are very likely to have blue-eyed children. What I think Mr. Hess is denying is the clear evidence that God *usually* acts within the physical laws he creates. Yes, he can override genetics and give a child any color of eyes he wishes--but under ordinary circumstances, we can safely count on God to follow the laws of genetics. Following Mr. Hess's statement that there are no laws of genetics, one could state that with each pregnancy they would have no idea if they would give birth to a human, a cat, or who knows what. How ridiculous! I'm not even sure how he thought this anti-probability chapter contributed to the central thesis of quiverfullness. If anything, it seems to take away from his argument, since if God is soveign and totally unpredicatable, then we have no reason to think that birth control would ever work anyway, so what would it matter if we use it?
While the book makes an excellent case that children are a blessing and that Christians should desire to be blessed with children, it doesn't make a Biblical case that the use of non-abortifacient birth control is "sin". I think many Christians would like the issue to be cut and dried, but the truth is, God does give us choices in life. Many times there are equally valid choices. Sometimes one choice is "better" than another choice, but that doesn't make the lesser choice "sin".
Still, many informative & interesting points are brought up in the book. It is a quick read, and probably worth the read for someone seriously investigating this subject. In my opinion a much better read on this subject is "Birthing God's Mighty Warriors" by Rachel Scott. ( )