We’re expecting our first and are only planning on having one (age, health plus other reasons) and despite what friends have said, we are not concerned about social ineptitude, isolation issues etc - that’ll be down to us to ensure our child doesn’t have these problems and therefore want to live under the stairs 
There was a fairly recent article in ‘TIME’ http://www.time.com/time/magazine/article/0,9171,2002530-1,00.html about peoples perceptions on people that do only have one child and the child itself - “About 120 years ago, an Amercian, Granville Hall, established one of the first American psychology-research labs and was a leader of the child-study movement. A national network of study groups called Hall Clubs existed to spread his teachings. But what he is most known for today is supervising the 1896 study “Of Peculiar and Exceptional Children,” which described a series of only-child oddballs as permanent misfits. Hall — and every other fledgling psychologist — knew close to nothing about credible research practices. Yet for decades, academics and advice columnists alike disseminated his conclusion that an only child could not be expected to go through life with the same capacity for adjustment that children with siblings possessed. “Being an only child is a disease in itself,” he claimed”.
The article goes on to desribe all of the pluses of being an only child and there are heaps, so it’s defintiely worth the read. I personally love this article as it means everyone that criticises our choice opts to not discuss the topic with us any further)