Sex differences in human physiology
Female fertility declines after age 30 and ends with the menopause. Female physical experiences vary depending on external forces such as diet, marriage patterns, culture, and other aspects. In Western nations menstruation begins to affect females at 13 and menopause starts around 51. In non-industrialized countries, on the other hand, most females begin menstruation at a later age. More lactation in the lifetime of non-western females inhibits ovulation and extends the number of fertile years. Pregnancy in the 40s or later has been correlated with increased risk of Down syndrome in the children. Males are capable of fathering children into old age. Paternal age effects in the children include multiple sclerosis, autism, breast cancer and schizophrenia, as well as reduced intelligence. Adriana Iliescu was reported as the world's oldest woman to give birth, at age 66. Her record stood until Maria del Carmen Bousada de Lara gave birth to twin sons at Sant Pau Hospital in Barcelona, Spain on December 29, 2006, at the age of 67. In both cases IVF was used. The oldest known father was former Australian miner Les Colley, who fathered a child at age 93.
Hormone replacement therapy
A major complaint among postmenopausal women is decreased libido, and many may seek medical consultation for this. Several hormonal changes take place during the menopausal period, including a decrease in estrogen levels and an increase in follicle-stimulating hormone. For most women, the majority of change occurs during the late perimenopausal and postmenopausal stages. Decrease in other hormones such as the sex hormone-binding globulim (SHBG) and inhibin (A and B) also take place in the postmenopausal period. Testosterone, a hormone more commonly associated with males, is also present in women. It peaks at age 30, but declines with age, so there is little variation across the lifetime and during the menopausal transition. However, in surgically induced menopause, instead of the levels of estrogens and testosterone slowly declining over time, they decline very sharply, resulting in more severe symptoms.