Skimming the list, I suspect that it wasn't entirely a coincidence -- most of her choices seem to be from series which (accurately or not) -I- personally would classify as supernatural romance -- a segment where women authors predominate.

In the greater sf/f sphere there are plenty of families in books by both men and women. Most epics -require- family ties of some sort... a good fraction of major plot themes involve sibling rivalry or some kind of parental issues.

How many books can you name where there are -no- related characters?