From memory, feminine curves are to do with the female hormones and their ratios, mainly Estrogen that is particularly to do with breast size. Which is pretty much a body part to attract men for reproductive purposes. They are called sexual organs for reasons. It is a natural weapon to attract men for high chance of breeding chances. Just like pheromones and female phermomones is produced from Estrogen.
0.7 waist-hip ratio is World Health Organization for female, while in popular culture also 0.7 ratio between the waist and hip for female is the most attractive that is similar to the animal kingdom for assessing if the female counterpart is healthy enough for child bearing. While for female above 0.85 that is the risk indicator of concerning health.
Using data from the U.S. National Center for Health Statistics,
William Lassek at the University of Pittsburgh in Pennsylvania and
Steven Gaulin of the University of California, Santa Barbara, found a child's performance in cognitive tests correlated to their mother's waist-hip ratio, a proxy for how much fat she stores on her hips. Children whose mothers had wide hips and a low waist-hip ratio scored highest, leading Lassek and Gaulin to suggest that fetuses benefit from hip fat, which contains long chain polyunsaturated fatty acids, critical for the development of the fetus's brain.In addition, evidence suggests that children of low-WHR teens were protected from the cognitive deficits often associated with teen birth.
http://en.wikipedia.org/wiki/Waist%E2%80%93hip_ratio
Scientifically speaking, fat tissues in the hips regions contain more Omega 3 and Omega 6 oil based fat which is essential for brain development for the fetus. Several Health Statistics from US also found that mother with this ratio seem to produce children scoring higher cognitive test. Also bigger hip/pelvic bone size is a great indicator of positive ability to physically carrying the fetus and bigger physical room to store more beneficial fat.
Basically smaller waist allows more room for the abdomen to expand for the growing fetus while an already overweight abdominal will restrict the internal womb's size for fetus' development as most likely the internal organs will also have more surrounding fatty tissues.
So in term of medical astrology, your natural body shape as well as in progression most likely reflecting your current reproductive hormones and health condition for reproduction as well as attractiveness to attract the opposite sex for reproductive purposes. A healthy ratio represents ultimate fertility. Too skinny or too overweight both can interrupt hormonal balances and menstrual cycles/quality of eggs etc. Just like what animals will do to show off they are healthy and ready for breeding. They change color of their skin or feathers or used of body languages or sound etc.
http://www.dailymail.co.uk/femail/a...To-tell-womans-really-attractive-figures.html
Physical Beauty to the eye in nature is a subtle measurement for reproductive health and fertility/stamina for sexual activity.
One interesting thing though the true fertility and attractiveness actually is the waist-hip ratio instead of the breast size through estrogen and breast size can be helpful to increase attractiveness to get to the mating act. Larger breast women without an equally healthy waist-hip ratio may actually experience more problems of falling pregnant due to overdrive of estrogen that is naturally sterile that what contraceptive pills made from anyway! Women do often find themselves having bigger breast when they have been on pills for a period of time.
This is an academic article from a health research journal I often used for my previous Health Promotion epidemiology unit. Reliable data.
http://www.cep.ucsb.edu/papers/whrlassekgaulin2008.pdf
The distribution of the upper and lower fatty tissues were studied to determine the link of cognitive level for both the mother and the offspring. It is funny if you thought of women with bigger bums and healthy 0.7 ratio are actually smarter!