I thought the programme was fab too. It was really interesting to watch. I can totally understand why the couple would have prefered to have a child with hearing loss.
a) They seem to have a very good close knit circle of deaf friends who sign. They were probably worried that the child would feel alienated from his immediate 'community' if he were hearing.
b) The girl (Claire) had a very positive upbringing in a household where everyone is deaf - her Mum, Dad and 2 brothers. So I can see that she would want the child to have a similarly positive and warm upbringing.
c) The father (Paul), didn't have a very positive childhood as a deaf person. It seemed to me that he wanted to give his son what he never had.
I agree that Paul's mother seemed very uncomfortable around deaf people, despite the fact that her 20-something son is a deaf person (you'd think she'd have had the chance to get used to it a bit by now, IYSWIM). I'm sure a lot of the strained relationship we saw was down to the fact that she recieved very dodgy advice re communicating with her son from the boarding school he attended ('DON'T LEARN TO SIGN').
Although I have to say that if one of my children was born with profound hearing loss, then I would make it my business to learn BSL and more about the deaf community well before my child was school-aged. I suspect she spent the first 5 years a bit shell-shocked, almost like if she ignored it, it would go away.
All in all I thought they were a very warm family. I did feel that Paul's Mum was a little bullied by Claire's Mum, although frankly I found it quite difficult to feel any real sympathy for her. I thought it was a real positive step when she said that she would learn signs for her grandson. It's just a shame that she didn't have the strength of her convictions back when her own son was tiny.