This suggests other factors. Could it be that many more have negative equity? That they are more "responsible" than men, and are more likely to buy houses? Or is there some other reason?
I'd guess a net worth of $5 probably equates to rented accommodation and hand-to-mouth existence: money in, money out, zero savings. Just coping. Is it worth noting at this point that a single woman with children will have far greater expenses than a man who doesn't pay child support?
Below that, credit card debt (or worse), maybe run up for necessities or as a result of sickness or unemployment.
you are the media you consume.