http://www.dailymail.co.uk/news/article-2218588/Ramjit-Raghav-Worlds-old...

It sounds like he's a pretty healthy 96, so while male fertility does start to decline at 35, there is still a chance that some men can father children in their 80's and 90's.

Also, she's 54, which makes me think this is one of those "pre-menopause" babies. (women become very fertile right before starting menopause)