It seems to me that this is a “pick your poison” situation. Marriage and childrearing has its own set of pitfalls, especially for men if the marriage goes bad. (Google “marriage strike”, or peruse Dr. Helen’s blog where this is a frequently recurring theme, and you’ll quickly see what I mean.) And even if you manage to avoid that, there’s any number of factors and circumstances that can land elderly parents in the same boat as single and childless elderly people. For instance, every U.S. soldier lost in Afghanistan or Iraq is one less person who can take care of his parents in their old age. Yet I’m not about to turn against either of those wars for that reason, and I doubt any of the other regulars here are either. (Well… maybe Teresita. :p )

If you’re single and without kids, you will have problems later in life if (1) you’re not prepared for it in advance and (2) you actually live long enough for that to become an issue in the first place. The former is up to you, but the latter is never guaranteed to anyone, especially as we enter the age of nuclear terrorism.