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
The maintenance and improvement of quality of life during the menopausal period is at the core of estrogen and progestogen-based HRT. Both HRT and estrogen replacement therapy (ERT) have been shown to enhance sexual desire in a significant percent of women; however, as with all pharmacological treatments, not all women have been responsive, especially those with preexisting sexual difficulties. ERT restores vaginal cells, pH levels, and blood flow to the vagina, all of which deterioration are associated with the onset of menopause. Dyspareunia (due to vaginal dryness) appears to be the most responsive component of menopausal women’s sexuality to ERT. It also has been shown to have positive effects on the urinary tract and atrophy and may initially improve libido or sexual sensitivity. Other improvements in areas such as sexual desire, arousal, fantasies, and frequency of coitus and orgasm have also been noted. However, the effectiveness of ERT has been shown to decline in some women after long-term use. A number of studies have found that the combined effects of estrogen/androgen replacement therapy can increase a woman’s motivational aspects of sexual behaviour over and above what can be achieved with estrogen therapy alone. Findings on a relatively new form of HRT called tibolone — a synthetic steroid with estrogenic, androgenic, and progestogenic properties — suggest that it has the ability to improve mood, libido, and somatic symptoms of surgically menopausal women to a greater degree than ERT. In various placebo-controlled studies, improvements in vasomotor symptoms, emotional reactions, sleep disturbances, somatic symptoms, and sexual desire have been observed. However, while this is and has been available in Europe for almost two decades, this has not been approved for use in North America at this point.