As the mother of four children, I tend to agree.
Although I have autistic children, I find that the presence of each other is very therapeutic. They have to learn to deal with each other and try to get along. They are getting life lessons they otherwise wouldn't get, because autism tends to isolate them from others. This isn't a dig at parents of autistic children who forego siblings-- it can be very draining to deal with them. But when parents of autistic children wonder whether they should have a second child, they should remember that another child can be beneficial to the kid they already have.
Via: Family Coalition Party