Starting at conception, the human body develops by neatly splitting cells. If every division were to go perfectly, the result would be a baby whose left and right sides are mirror images. But nature doesn't work that way. Genetic mutations and environmental pressures skew symmetry, and the results have lifelong implications.
Good symmetry shows that an individual has the genetic goods to survive development, is healthy, and is a good and fertile choice for mating.
"It makes sense to use symmetry variation in mate choice," said evolutionary biologist Randy Thornhill of the University of New Mexico. "If you choose a perfectly symmetrical partner and reproduce with them, your offspring will have a better chance of being symmetric and able to …show more content…
And scientists have some numbers to prove it. Psychologist Devendra Singh of the University of Texas studied people's waist-to-hip ratio (WHR).
Women with a WHR of 0.7—indicating a waist significantly narrower than the hips—are most desirable to men.
And an analysis of hourglass figures of Playboy models and Miss America contestants showed that the majority of these women boast a WHR of 0.7 or lower.
In general, a range of 0.67 to 1.18 in females is attractive to men, Singh concluded in a 2004 study, while a 0.8 to 1.0 WHR in men is attractive to women, although having broad shoulders is more of a turn-on.
What exactly is encoded in the hip ratio? A big fat clue to whether the person will have enough energy to care for offspring.
Where fat is deposited on the body is determined by sex hormones; testosterone in men and estrogen in women. If a woman produces the proper amount and mixture of estrogen, then her WHR will naturally fall into the desired range. The same goes for a male's testosterone.
People in the ideal hip-ratio range, regardless of weight, are less susceptible to disease such as cardiovascular disorders, cancer, and diabetes, studies have shown. Women in this range also have less difficulty …show more content…
"We think the detection of these types of scent is way outside consciousness," Thornhill said.
A 2002 study found women prefer the scent of men with genes somewhat similar to their own over the scent of nearly genetically identical or totally dissimilar men.
These subconscious scents might be related to pheromones, chemical signals produced by the body to communicate reproductive quality. The human genome contains more than 1,000 olfactory genes—compared to approximately 300 genes for photoreceptors in the eyes—so pheromones have received a lot of attention from basic research scientists as well as perfume manufacturers.
But the role of pheromones in the human realm remains controversial.
Animal attraction
Pheromones clearly act as sexual attractants in the animal world. Older male elephants, for example, exude sexual prowess with a mix of chemicals the younger bulls can't muster.
Milos Novotny of the Institute of Pheromone Research at Indiana University has shown that special molecules produced by male mice can simultaneously attract females and
Good symmetry shows that an individual has the genetic goods to survive development, is healthy, and is a good and fertile choice for mating.
"It makes sense to use symmetry variation in mate choice," said evolutionary biologist Randy Thornhill of the University of New Mexico. "If you choose a perfectly symmetrical partner and reproduce with them, your offspring will have a better chance of being symmetric and able to …show more content…
And scientists have some numbers to prove it. Psychologist Devendra Singh of the University of Texas studied people's waist-to-hip ratio (WHR).
Women with a WHR of 0.7—indicating a waist significantly narrower than the hips—are most desirable to men.
And an analysis of hourglass figures of Playboy models and Miss America contestants showed that the majority of these women boast a WHR of 0.7 or lower.
In general, a range of 0.67 to 1.18 in females is attractive to men, Singh concluded in a 2004 study, while a 0.8 to 1.0 WHR in men is attractive to women, although having broad shoulders is more of a turn-on.
What exactly is encoded in the hip ratio? A big fat clue to whether the person will have enough energy to care for offspring.
Where fat is deposited on the body is determined by sex hormones; testosterone in men and estrogen in women. If a woman produces the proper amount and mixture of estrogen, then her WHR will naturally fall into the desired range. The same goes for a male's testosterone.
People in the ideal hip-ratio range, regardless of weight, are less susceptible to disease such as cardiovascular disorders, cancer, and diabetes, studies have shown. Women in this range also have less difficulty …show more content…
"We think the detection of these types of scent is way outside consciousness," Thornhill said.
A 2002 study found women prefer the scent of men with genes somewhat similar to their own over the scent of nearly genetically identical or totally dissimilar men.
These subconscious scents might be related to pheromones, chemical signals produced by the body to communicate reproductive quality. The human genome contains more than 1,000 olfactory genes—compared to approximately 300 genes for photoreceptors in the eyes—so pheromones have received a lot of attention from basic research scientists as well as perfume manufacturers.
But the role of pheromones in the human realm remains controversial.
Animal attraction
Pheromones clearly act as sexual attractants in the animal world. Older male elephants, for example, exude sexual prowess with a mix of chemicals the younger bulls can't muster.
Milos Novotny of the Institute of Pheromone Research at Indiana University has shown that special molecules produced by male mice can simultaneously attract females and