[Sex differences over time in bone development and maintenance and their mechanisms]

There is a clear, sex-related difference in speed of bone development in favor of female infants over that of females infants, with an excess of estrogen secretion at this stage likely accounting for the difference. In this, females appear to benefit by their high level of estrogen secretion which is three times that in males. However, males are less susceptible to a drastic change in bone density even at a greater age, as they are able to develop and maintain bone mass with a much lower but constant level of estrogen than that required in females. In contrast, females undergo a drastic change in estrogen levels after menopause and are hardly able to arrest bone resorption, thus suffering a steep fall in bone mass. Thus, there is also a clear difference in bone development and maintenance over time between sexes, the reason likely being a drastic rise or fall in estrogen levels over time.