For some, factors such as whether the person smokes, is fat or wants children will override biological compatibility, said Helen Fisher, a biological anthropologist and author of "Why Him? " She believes genes play a role but said it's only one part of the puzzle.
"They can't be sued for not following this, but it puts them in the public eye," she said.Match.com, e Harmony and Spark Networks signed a joint statement of business principles intended to provide an example for the industry and help guard against sexual predators, identity theft and financial scams."Consumers should be able to use websites without the fear of being scammed or targeted," Attorney General Kamala D. Among other things, the companies agreed Monday to check subscribers against national sex registries, supply members with online safety tips, and provide a quick way to report abuses.Biologists say the HLA genes of the immune system — which are responsible for recognizing and marking foreign cells such as viruses so other parts of the immune system can attack them — also determine body odor "fingerprints." And people tend to be attracted to the natural body odors of those who have different HLA genes from their own.In one study, Swiss biologist Claus Wedekind found that women who were not taking hormonal contraception preferred the natural scent of men whose immune systems were the most different from theirs.In fact, he is planning to phase out the dating part of the site he started in 2007 to market the tests directly to matchmakers and couples.He promises a refund of the 5 lifetime membership. "How many dating services can you think of where they can suggest you might have better children? The companies claim that a better biological match will mean better sex, less cheating, longer-lasting love and perhaps even healthier children.The statement was prompted by the 2010 sexual assault of a Los Angeles-area woman by a man she met through Match.com, Gledhill said.Alan Wurtzel had a string of previous convictions for sexual battery.