Are you familiar with any information regarding bonding issues related to C-sections? Thanks.

I have not heard anything about a controversy about this but I think I know where they are going with it. The peptide oxytocin is one of the compounds generated by the body associated with bonding. During the birthing process the stretching of the vagina increases oxytocin levels, which in turn stimulates the uterine contractions that pushes the fetus out.  Taking a baby by c-section avoids this increased oxytocin level so they would assume that this would reduce bonding between the mother and baby. 

This is not the only bonding factor though, nor the only method of increasing oxytocin. After birth the babies sense of smell plays a role in the bonding process with the mother as with many other animals. And oxytocin is also increased by nipple stimulation such as breast feeding. Therefore breast feeding further promoted mother-baby bonding if the mother does in fact breast feed.