Sabine Walter

An anonymous writer put it this way: "Friends in your life are like pillars on your porch. Sometimes they hold you up and sometimes they lean on you. Sometimes it's just enough to know they're standing by." ©Seventyfour / Adobe StockWriter Elisabeth Foley points out that friendship doubles your joy and divides your grief, and that the most beautiful discovery that true friends make is that they can grow separately without growing apart.

If a couple tries to conceive but can’t seem to do it, one of the first things that doctors look for is a problem with the man’s sperm. Sperm compose about 5 to 10 percent of semen, and are the only part of the semen that can cause pregnancy. If a man is infertile, there is a problem with his sperm — often a low sperm count or low motility.

Knowing how a penis functions can provide useful insight into sex and the human body — whether you want to understand the penis and male anatomy better or learning about it for the first time. Basically, a penis is composed of three structures, which are made of a spongelike material that can fill with blood: The two corpus cavernosa contain the central arteries and lie on the top half of the penis.

Understanding women's sexual (or reproductive) organs such as the vagina, uterus, and vulva is as integral to sex as understanding the penis. Demystifying female anatomy is key to good sexual functioning, whether you're a mature, experienced adult or looking to learn about women's sexual organs for the first time.

If you’ve heard of only one STD, it's probably AIDS (acquired immunodeficiency syndrome), which is linked to infections by HIV (human immunodeficiency virus). Why is so much more attention given to HIV/AIDS than to any other sexually transmitted disease? Because AIDS is deadly, and it has no cure and no vaccine.

What is sex, exactly? In other words, what "counts" as having sex? And when do you stop being a virgin? Sexual relations cover activities beyond intercourse: They also include outercourse, oral sex, and anal sex. So what are the differences and how do they impact virginity? One thing that all forms of sex (outercourse, oral sex, anal sex, and intercourse) have in common is that they involve two people giving each other the pleasure that comes from having an orgasm.

What's commonly called a permanent erection is an erection that won’t go away within four hours; the medical term for this condition is priapism. In priapism, blood becomes trapped in the penis and cannot flow out. A permanent erection isn't a sign of masculinity, but of a true medical problem. Anyone who has an erection that won’t go away even after orgasm/ejaculation should seek medical treatment or head to the emergency right away.

Impotence — meaning, the inability to have an erection when desired — frightens men, even though many have suffered from impotence at some point. Men may confuse short-term impotence with erectile dysfunction. The good news is that a couple of failures to have an erection doesn't mean there's something wrong with your penis.

People often refer to safe sex methods simply as birth control or contraception. Many contraceptive methods do a great job of preventing pregnancy, but don't offer any protection against sexually transmitted diseases (STDs). Before you make a choice about the right protection for you, it’s important to understand all the options available for safe sex, how contraception works, and if your chosen method of safe sex also protects against STDs.