By Wingki Kwok

Effect of dropping sperm counts on fertility rates

In a typical sex act, an average male ejaculates about 300 million to 400 million sperms.

However, the British Medical Journal reported a sign- ificant drop of 41.6 percent in the mean sperm count in the past few decades.

The sample size was 15,000 men and the actual decrease was from 113 million spermatozoa per millilitre in 1938 to 66 millions per millilitre in 1991.

Prof. Chan King Ming of the Department of Biochemistry at The Chinese University of Hong Kong said that endocrine disrupting chemicals affect male fertility.

These chemicals are found in river beds or in the form of suspended particles.

Nonetheless, Prof. Simon Au of the School of Medicine at The Chinese University of Hong Kong said that the validity of the report was questionable.

Apart from the debate on sperm count changes, Prof. Au said the drop in sperm counts has little effect on fertility rates.

Said he: “According to the criteria set by the World Health Organisation, a normal sperm count should be more than 20 million per millilitre. Any variation above this level does not have significant effect on fertility rates.

“The fertility rate may decrease if the sperm count is less than the minimum level, but this does not mean a person is infertile.”

He said fertility also depends on sperm quality, which includes the sperm mobility and the volume of ejaculated semen.

The World Health Organisation suggested that the minimum sperm mobility — that is, the swimming ability of sperms, — should be at least 50 percent progressing forward and 25 percent progressing rapidly.

The minimum volume of ejaculated semen is 2 millilitres. Dr. Lai Yin Tung, a masculinologist, agrees that there is a trend of dropping sperm counts.

“Statistics in our own clinic show that, for an infertile couple, most problems are found in the male rather than in his partner.

“These problems include low sperm concentrations and activity.”

The average sperm count, according to Dr. Lai, is between 60 million and 100 million per millilitre.

She said her patients usually have sperm counts lower than the average. Prof. Au said that there are individual and global factors contributing to the phenomenon.

Factors affecting sperm counts

1. Individual lifestyles

“Temperature is a vital factor in sperm production. Wearing jockey shorts increases the temperature of the testes, which is unfavourable to sperm production.

“It would be better to wear boxer shorts,” added Prof. Au.

He said some members of certain occupations such as bakers and drivers may be vulnerable in the sense that they have to work in hot environments.

“Regular hot baths may also lead to declining sperm counts,” he said.

Although sperm production is related to temperature, Prof. Au said declining sperm counts are not likely to be related to global warming.

Lifestyles may also affect sperm counts.

“Drinking is bad for the liver and testes.

“Yet so far only one report indicates a significant relationship between sperm quality, smoking and excessive consumption of coffee.

“It was suggested that smoking more than 20 cigarettes and drinking more than four cups of coffee may lead to low sperm activity and more dead sperms, though caffeine can stimulate sperm activity in external use,” he said.

Prof. Au said that although no scientific evidence establishes the effects of coffee, heavy smoking and drinking on sperm counts, patients are usually encouraged to give up these habits.

Said he: “Stress is another factor that affects a male’s hormonal level and in turn sperm production.

“Besides, drugs containing lead or mercury have large damaging effects on sperm quality and quantity. Also, anti-fungal drugs inhibit sperm production.”

He said radiation is not a global factor in decreasing sperm counts, unless men are accidentally exposed to it or in case of therapeutic use in cancer treatment.

2. Endocrine disruptors

A major global factor leading to declining sperm counts is environmental pollution.

Said Prof Au: “Declining sperm counts are also common among wild animals like polar bears and fishes.”

He said that the major reason is the pollutants in their living environment.

Many environmental pollutants are known as endocrine disruptors.

These substances upset sperm production.

Said Prof. Au: “The endocrine disruptors probably disturb male infant development.

“This results in small testes and in turn lower capacity for sperms.”

In serious cases, these disruptors lead to cryptorchidism. This means that one or both testes remain inside the abdomen of the infant.

“If it happens to both testes, there is a high possibility of infertility.”

These endocrine disruptors come from the environment and dietary sources.

“Plastics used to make milk bottles contain endocrine disruptors that are released under high temperature.

“Some industrial detergents, pesticides or herbicides contain these compounds. We take in these compounds if they are not washed away.”

The European Union imposed a prohibition on 24 November 1999 against selling certain types of plastic in baby toys.

These plastics also contain endocrine disruptors.

3. Well-being of the reproductive system

Both Prof. Au and Dr. Lai agree that sexual diseases have a strong impact on sperm count and quality.

Prof. Au said sexual gland infections may lead to changes in the biochemistry of semen and thus affect the fertilising power of sperms.

Said he: “Having too many sexual partners means a higher chance of contracting sexual diseases. Thus, sperm quality and quantity may be affected.

“People should have some basic knowledge about the reproductive system and sexual diseases, and they should beware of personal hygiene.

“Frequent sexual intercourse may be another factor. Since sperms need around two months to develop, the production cannot compensate the loss. Low sperm concentration and immature sperms result.”

Prof. Au said that testicular cancer affects the normal functioning of testes and hence sperm production.

Chemotherapy further damages the remaining normal testes, leading to a significantly impaired fertility. In the most serious case, the testes have to be cut away.

Said he: “The frequency of testicular cancer is not high in Hong Kong.

“But certain countries like Demark reflect an increasing number of cancer patients in recent years, for unknown reasons.”

For men who have low sperm concentrations, hormonal treatments may help.

Said he: “In fact, little can be done if the patient’s hormone level is normal.”

4. Nutrition

Prof. Au said there is not much relationship between nutrition and sperm count.

But Prof. Leung Chung Ming of the Department of Chinese Medicine at The Chinese University of Hong Kong holds a different stance on dropping sperm count.

“To retain the normal sperm count, a healthy reproductive system is important for its relation to the digestive system.”

Said he: “A good digestive system implies easy absorption of nutrients.

“Sufficiency of nutrients is beneficial to the body, including the reproductive system and hence sperm production.”

Dr. Lai specialises in masculinology, which employs both Western and Chinese medicine approaches.

She agrees with the importance of good nutrition.

“Processed foods like instant noodles contain little nutrients but unwanted materials such as glutinous substances.

“Eating more natural and raw food is better,” Dr. Lai said.

The Chinese medical practitioners also emphasise the effect of emotions on sperm counts.

Prof. Leung of the Department of Chinese Medicine said, “The well being of our reproductive system is influenced by our emotional state.

“Adverse emotions and stress hinder sperm production. The Chinese medical practitioners believe the importance of internal harmonies of a body. Reproduction is related to other body systems.”

He suggested that more nutritious food, exercise and relaxation are keys to maintain a good reproductive system.