Sexual Motivation
Sex is part of life.
Sexual motivation is nature’s clever way of making people procreate; enabling our species survival.
Pleasure of sex is our genes’ way of preserving and spreading ourselves.
First description of sexual behavior in the United States came from Alfred Kinsey {Indiana University biologist}
I. Unable to answer students questions about sexual practices
II. Kinsey went out to find answers; his research was controversial
III. His statistics-laden volumes became bestsellers
Most men and nearly half the women reported having had premarital sexual intercourse
A. Most women and virtually ALL men reported having masturbated
B. Women who reported masturbating to orgasm before marriage seldom had difficulties experiencing orgasm after marriage
C. Some men and women said they had never had an orgasm
D. Others reported having four or more a day

The Sexual Response Cycle
The four stages of sexual responding described by Masters and Johnson
1. Excitement
The genital areas become engorged with blood
Women’s vagina expands and secretes lubricant – breasts and nipples may enlarge
2. Plateau
Excitement peaks when breathing, pulse, and blood pressure rates increase.
Penis becomes fully enlarged
Containing enough live sperm to enable conception (appears on tip)
Vaginal secretion increases
Clitoris retracts, orgasm feels imminent
3. Orgasm
Muscle contractions all over the body
Accompanied by increases in breathing, pulse, and blood pressure
Woman’s arousal and orgasm facilitate conception { positioning the uterus to receive sperm }
Woman’s orgasm not only reinforces intercourse, it increases retention of deposited sperm
4. Resolution
Refractory period
A resting period after orgasm, during which a man cannot achieve another orgasm
Lasts only a few minutes, a day or even more
Cannot have another orgasm
Females have a shorter refractory period
Can have another orgasm if restimulated during or soon after resolution
Sexual Disorders
A problem that consistently impairs sexual arousal or functioning
Men
I. Premature ejaculation
II. Erectile dysfunction { inability to have or maintain an erection } (routinely treated by taking a pill)
Women
I. Orgasmic disorder { infrequently or never experiencing orgasm }
Men or women with sexual disorders can often be helped by receiving behaviorally oriented therapy
Men learn ways to control their urge to ejaculate
Women are trained to bring themselves to orgasm
Hormones and Sexual Behavior
Sex hormones have two effects
I. The physical development of male and female sex characteristics
II. Activate sexual behavior
Estrogen
A sex hormone, secreted in greater amounts by females than by males.
In nonhuman female mammals, estrogen levels peek during ovulation, promoting sexual receptivity.
Testosterone
The most important of the male sex hormones
Males and females have it
Additional testosterone in males stimulates the growth of male sex organs { in the fetus}
Development of the male sex characteristics during puberty
Hormones more loosely influence sexual behavior
Sexual desire rises slightly at ovulation among women with mates
One study invited women { who were not at risk for pregnancy } to keep a diary of their sexual activity
i. The women either used intrauterine devices or had undergone surgery to prevent pregnancy. ii. Days around ovulation, intercourse was 24% more frequent
Women’s natural testosterone level drops, sexual interest may wane.
Testosterone-replacement therapy Restores diminished sexual appetite
Menopausal women found that a testosterone-replacement patch restored sexual activity
In men testosterone levels have little effect on sexual drive
Normal short-term hormonal changes have little effect on men’s and women’s desire
Large hormonal shifts over the lives of men and women have greater effect.
i. People’s interest in dating and sexual stimulation usually increases with pubertal