I'm not really sure about this because researchers seem to be able to link just about anything to just about everything! An orgasm is pure medicine, I'm not kidding you! Men have to have one in order to procreate but women have that particular 'equipment' for one reason only - pleasure. So why they don't make the most of it, as often as possible, is beyond me. It helps with stress, reduces insomnia, and sex is great exercise. I am no therapist but I think an underlying reason women refuse sex is not fatigue or headaches but because they have an underlying anger or resentment against their partner - for whatever reason. A lot of women withhold sex as a kind of passive-aggressive punishment. It's their one way of 'getting back' at the guy. With a 4, 2 and 1 year old, I understand fatigue and burnout but you simply have to put the effort in. Your partner, and you (!) deserve it! I'm not prancing around in my lingerie every night of the week but sex in a relationship is very important - there is no denying that. Good sex is great sex and why would a woman turn that down! I wouldn't turn down a great cocktail because I was mad at the bartender! So the research may be accurate but I remain a little skeptical!