I'd be interested in seeing any research you may have seen that supports your position. Anecdotally, that hasn't been my experience (in those around me, obviously)
However, I see that there is nothing in the article specifically about primary caregiver being female. To summarize, it is better to have one primary caregiver who has established a strong attachment with child. Traditionally it has been a female role, and I do believe women are better suited for it.
Also, I am always suspisous of 2nd hand science reports, especially when they do not provide a direct link to the original paper(s). If anyone does track down some research papers on the subject, please post it here.