Didn't the University of Wisconsin publish a study in 2000 that stated much of the same? If I remember correctly, it was quite the buzz for a few days, then the women's lib groups started to bring out their experts to quickly repudiate it and it just went away.
It is vital to the left to keep trying to convince the public that mothers and fathers are not important and that a village can better raise a child.
I just finished reading "Generation ME" by Jean Twenge (the book got some major press a few weeks back in a story about her research into increasing narcissism among college students). She makes sense in the first few chapters, and even suggests that the increasing epidemic of ADD among kids is the obvious result of poor parenting by GenME's, but in the latter chapters she goes off the deep feminist end, trashing all studies such as this and the one you mentioned, and fiercely advocating for state-sponsored daycare and public pre-preschools so all those highly-educated womyn with high-powered positions can reproduce and drop the kids into the taxpayers' lap. She also advocates for extended maternity leave -- but no so eloquently, since, in her words, "you might find yourself cooped up with young children every day and let's face it -- who is really prepared for that?"
The obvious question, of course, is: why have kids if you don't want to be to be bothered raising them?
I find it interesting that they had to do a study, but as pointed out in the article, they tried not to come to this conclusion.
For years I've felt there are so many brats and bullies because they had to fight for attention and for personal space in a day care setting.