About six days after a sperm fertilizes an ovum, it attaches itself to the uterus. This process is known as implantation.

See erectile_dysfunction

A term commonly used by sex therapists and researchers to describe a clinical syndrome that is characterized by a man or woman's experience of sexual urges, fantasies and behaviors that are recurrent, intense and distressing in their lives, and that may cause problems in their romantic or family relationships, in their work or school lives, or with the law. Men and women with this syndrome may perceive their behavior to be uncontrollable, and may be treated in couples therapy, individual therapy or sex therapy. .

A type of infertility treatment in which ova and sperm are combined in a petri dish under carefully controlled conditions to create one or more embryos. The resulting embryos are then transferred to a woman's uterus. In vitro fertilization is often performed after artificial insemination has proven unsuccessful. Donor eggs or a sperm bank donation may be used.

Involuntary leakage of urine from the urethra or feces from the anus. Urinary incontinence may be the result of childbirth, aging, surgery for prostate cancer and menopause, which weaken the pelvic floor. Fecal incontinence may be the result of childbirth, aging, constipation, diarrhea, and muscle or nerve damage. Kegel exercises are a common treatment or preventative behavior for incontinence.

A type of psychological counseling for an individual dealing with personal or interpersonal problems. Individual therapy can be short-term or long-term and is helpful for: addiction; codependence; emotional affairs and infidelity; a lack of emotional intimacy; low libido; compulsive use of erotica, compulsive multiple love relationships or impulsive/compulsive sexual behavior; and past or present emotional abuse, physical abuse, sexual abuse or verbal abuse. (see couples therapy, sex therapy)

One of three phases that may occur in romantic relationships, based on research by anthropologist and neuroscientist Helen Fisher. The infatuation phase comes after the initial lust phase and may last for 1-3 years before a couple settles into the attachment phase. The infatuation phase is associated with different chemicals in the brain, in particular high levels of dopamine and low levels of serotonin.

A woman is considered to be infertile when she is not able to get pregnant or carry a baby to term. Or, in the case of a man, the inability to fertilize an ovum. See infertility.

The inability to achieve and sustain a pregnancy after one year of regular vaginal intercourse, including repeated miscarriages. Female factors account for one-third of infertility cases, and may include: anovulatory cycles; PCOS; lack of fertile cervical fluid (or spinnbarkeit); STIs; stress; endometriosis; and pelvic inflammatory disease. Male factors account for another one-third of cases, and may include: problems with the quality or quantity of sperm production; STIs; and stress. The remaining cases are the result of factors in both partners or unknown factors. Aging, unhealthy lifestyle choices, and certain medications and health conditions also increase the risk of infertility. Treatment options for infertility include: FAM, artificial insemination, in vitro fertilization, and use of donor eggs or a sperm bank donation.

The act of being unfaithful to a partner in a monogamous relationship, which may include emotional affairs in addition to sexual activity.

When a man is unable to ejaculate during vaginal intercourse due to psychological or physical reasons. This is also referred to as inhibited male orgasm.

A condition that affects men and women. In men, the inability to achieve or maintain an erection for vaginal intercourse. In women, the inability to lubricate naturally to enable pleasurable vaginal penetration. Similar to ISD, the causes of ISA can be psychological, physical or related to medication. In some cases, it may be beneficial to have hormone levels tested. Talking with a OB/GYN, sex therapist or other trained professional can be helpful to uncover the cause and expolre feelings that are associated with issues related to arousal.

A condition that can occur in men and women that results in a lack of sexual desire. ISD can be short or long term, and is primarily caused by psychological reasons including sexual abuse or shame about sex or relationship issues including lack of communication or limited time to nurture the relationship. Physical conditions that cause pain or fatigue or side effects of medication can also be the culprit. Some people never have experienced desire. Others may have had desire diminish over time. In some cases, people with ISD are turned on by other people, but not by their partner. ISD is usually only an issue when two people in the relationship have different levels of desire. If two people both have low or no sexual desire, but are happy with each other and their relationship, it is not necessarily a cause of concern. In men and less reliably in women, testosterone levels can be tested. Talking with a sex therapist or other trained professional can help individuals and couples dealing with ISD.

When sperm enter the female reproductive tract to enable fertilization. Assisted fertilization is called artificial insemination.

Sexual activity involving penetration of the vagina, anus or mouth. Types of intercourse include: oral sex, anal sex and vaginal intercourse.

A condition in which a person is born with genitals or reproductive organs that do not fit a culture's typical definitions of male or female. Klinefelter syndrome, androgen insensitivity Syndrome and Turner syndrome are examples of conditions that fall under the umbrella term of intersexuality.

A chronic bladder condition with no known cause. Symptoms may include: the frequent urge to urinate; pain, pressure and tenderness in the bladder and perineum; and pain during intercourse. Unlike a urinary tract infection, no cause of interstitial cystitis can be found. Symptoms may be managed with dietary modifications, pelvic floor treatment, and anti-histamines and anti-depressants. Symptoms of interstitial cystitis in men may be similar to prostatitis.

See IUD

An entrance or opening to an organ, specifically the opening of the vagina. The introitus is rich in nerve endings and sensitive to stimulation during sexual activity, especially vaginal intercourse. Vaginal childbirth and an episiotomy may tear the introitus, affecting genital sensation. The introitus is flanked on either side by the Bartholin's Glands, which play an important role in lubrication during sexual arousal. The introitus is considered part of the genitals, or vulva.

See inhibited sexual arousal

See inhibited sexual desire

(short for intrauterine device) A form of birth control consisting of a T-shaped device inserted into the uterus through the cervix. An IUD prevents sperm from entering the uterus, stops ovulation and/or makes the uterus unfriendly for an embryo to implant. Two kinds of IUDs are available: ParaGard® and Mirena®. ParaGard is hormone-free and Mirena uses a low-dose of synthetic progesterone. ParaGard can remain in place for up to 12 years, while Mirena does so for up to 5 years. Benefits of an IUD include: a high rate of effectiveness and convenience, since it requires no interruption of sex play and can be kept in place for years. Side effects may include: heavier periods (ParaGard); lighter or absent periods (Mirena); spotting; and risk of expulsion. An IUD provides no protection against STIs and increase a woman's risk of pelvic inflammatory disease and infertility if she contracts an STI.