They might be having sperm count problems. According to research, sperm count affects 10% (or about 6.1 million) Americans in the reproductive age. Contrary to myth, sperm count is not always a "woman's problem." A third of the cases (about 35% are actually due to male sperm count factors.

Sperm count in men may be caused by many factors such as low sperm count (or nothing at all), ejaculation problems, or "abnormal" sperm, which is said to be malformed and have a short life span.

Generally, your fertility is based upon your general health. If you live a healthy lifestyle, there is a high probability that your sperm will also be healthy. There are quite a number of threats that may affect male fertility. Nicotine, alcohol and drugs (e.g., marijuana and cocaine) are on the top of the list. According to studies, smoking drastically decreases the sperm count and overall health of sperm cells.

Poor diet (malnutrition) can also contribute to male sperm count, including deficiency in vitamin C and zinc in your diet. Some diseases (e.g., tuberculosis, fevers, anemia, and mumps in adulthood) and infections are also suspect. These are infections of the reproductive system such as epididymitis, orchitis, and prostatitis. Some sexually transmitted disease such as chlamydia or gonorrhea also damages the spermatic ducts. You also risk transmitting your disease to your partner causing her to be infertile.

Some medications are also believed to be causes of male sperm count. This include cancer-treating agents (e.g., chemotheraphy), anti-fungal medication (ketoconazole), antidiarrheal drug (sulfasalazine), Azulfidine (a drug used to treat ulcerative colitis), and some groups of antibiotics (nitrofurans and macrolides). Likewise, the use of anabolic steroids is also known to cause testicular shrinkage and sperm count.

Other threats to male fertility also include testosterone deficiency, trauma or injury to the testes, structural abnormality or blockage in the vas deferens, and varicocele, a varicose vein in the testicle that produces too much heat harming and killing sperm count.

Some are also connected to your lifestyle, like excessive stress, overly intense exercise (may lower your sperm count by producing higher levels of adrenal steroid hormones, which lower the amount of testosterone in the body), tight underwear or jogging pants, hot tubs, saunas, or anything that raises the temperature of your scrotum, including overheated vehicles and hot work environments, and exposure to environmental hazards such as pesticides, lead, paint, mercury, benzene, boron, radiation (x-ray), radioactive substances, and increased sperm count.

Daily sex makes for healthier sperm (ABS-CBNNEWS.com)
LONDON – Having sex every day improves the quality of men's sperm and is recommended for couples trying to conceive, according to new research.

Study: More sex may help damaged sperm (USA Today)
For men with fertility problems, some doctors are prescribing a very conventional way to have a baby: more sex. In a study of 118 Australian men with damaged sperm, doctors found that having sex every day for a week significantly reduced the amount of DNA damage in their patients' sperm.

Avoid or Ignore? 11 Sperm-Killing Suspects (ABC News)
Experts discuss sperm count myths and what factors really do hit below the belt.

Serious cyclists 'risk sperm damage' (Guardian Unlimited)
Intensive cycle training such as that undertaken by triathletes has a negative effect on sperm quality, researchers tell the European fertility conference Too many hours in the saddle may affect the fertility of serious cyclists, a conference heard today. Researchers told the European fertility conference that cycle training of the intensity undertaken by triathletes has a significant impact on ...

Daily sex keeps sperm in shape (Australian Broadcasting Corporation)
Men trying to conceive with their partner should have sex every day to improve the quality of their sperm, according to new research.

The daily grind: Sex for a week boosts sperm quality (AFP via Yahoo! News)
Men seeking to become a dad should have sex each day, or ejaculate daily, for a week before their partner ovulates in order to maximise sperm quality, according to a study presented on Tuesday.