A man and a woman are considered infertile if they cannot produce a pregnancy after twelve months of trying. For centuries, the lack of ability to have children was blamed only on women. Scientists now know that men, too, can be infertile.

The organization PATH says infertility affects an estimated sixty-million to eighty-million people. It says the great majority live in developing countries. PATH is the Program for Appropriate Technology in Health. This non-profit group is in Seattle, Washington.

There are many different causes of infertility. Some are genetic. Others involve physical problems or injuries. Still others are environmental, like pesticides and other chemicals. Experts say diet and the use of alcohol and drugs can also affect fertility.

Some of these causes are preventable. So are others, such as infections spread through sex. Dirty conditions during childbirth can also cause infections that make women infertile. So can unsafe ways to end unwanted pregnancies. And so can the tradition in some cultures of cutting the female sex organs.

In industrial countries, the best-known current treatment for infertility is a process called in vitro fertilization. This involves joining an egg with sperm in a laboratory. Once fertilized, the egg is placed in the woman to develop into a fetus. Treatments can also involve the use of fertility drugs to increase the production of eggs.

But experts say cultural and religious beliefs may prevent people from seeking modern treatments. In Italy, for example, a new law took effect this month. The Medically Assisted Reproduction Law restricts or bans the use of many kinds of technologies. In other societies, people often blame evil spirits when a couple cannot have children. So people seek traditional treatments.

In any case, technologies for assisted reproduction cost thousands of dollars. So public health systems usually do not offer them. Many experts say public health systems should do more to educate people about preventable causes of infertility. These include sexually transmitted diseases.

The experts also say doctors should require an examination of both the man and the woman when a couple is infertile. The group PATH says men are the cause, or part of the cause, of infertility in more than half of couples.

This VOA Special English Development Report was written by Jill Moss. This is Bob Doughty.