Does Security Reduce Women's Sex Drive?

The BBC recently released a story claiming that security in a relationship reduced a woman's sex drive. I first saw this on www.steamingpile.blogspot.com. The study intervied more than 500 men and women and found that women over 30, who had beed in a committed relationship for 4 years or more had a decreased desire for sex while their male counterparts desire remained the same despite the precieved "security" of the relationship.
The decrease in women's sexual appetites is attributed to the belief that they have formed a "pair bond" with their partner and with that accomplished, they don't feel the need to secure the male any more (and may have their sights on another). Another explination is that of "supply and demand".
This is an interesting study but I believe they forgot one very important factor: children. My guess is that the majority of women who are over 30 and have been in a comitted relationship for more than 4 years have children. Call me crazy,but I think a screaming child could have just as much if not more of an affect on a woman's sex drive as a sense of security.
As for the man's unaffected sex drive. Its a stereotype but also a proven statistic that women are still the primary care givers to children. If you want to put it in the human evolutionary light used previously: men are are genetically programmed to produce as many offspring as possible while women are more concerened with the survival and care of the current offspring and therefore less inclined to increase their numbers.
The financial strain that children can put a couple,s finances also should not be overlooked as far as sex drive is concerned. Money is listed as one of the top 5 reasons that couples fight and if a couple is consistantly fighting, they're probably not in the mood for romance.