About 5,000 infertile couples in Guangdong province are looking for sperm donors, but as many as 80 percent of them have failed due to limited supply, the provincial sperm bank said on Monday.

Infertility is becoming a serious problem, with approximately one in six couples experiencing difficulties conceiving during their reproductive life. In around a third of these, failure to achieve pregnancy is due to an abnormality or possibly an absence of spermatozoa in the male partner's semen.

"I have been married to my husband for five years, but we failed to have a baby as my husband is infertile," Yang, a Guangzhou resident in her 30s, said.

Yang's husband, also in his 30s, who only identifies himself as Cheng, was diagnosed with an absence of sperm in his semen last year. The diagnosis ruined their dreams of having a child.

Artificial insemination using sperm from an anonymous donor is an option by which this couple may have a family.

In December last year, they visited the Guangdong human sperm bank, which is a subsidiary of the Guangdong Family Planning Hospital.

"When we submitted our request, we were told that we probably would have to wait for a long time as thousands of couples are also seeking sperm there," Cheng said.

"About 5,000 couples have submitted requests for artificial insemination by donor since 2001, though only about 1,000 of them have successfully found proper sperm donors," Tang Lixin, the director of the sperm bank, told China Daily.

The bank only has a few thousand qualified sperm donations available.

There are several reasons why the sperm supply has fallen short, he said.

In the past few years, only about 28 percent of the donated sperm is qualified for use in artificial insemination.

The normal density of sperm in semen is 20 million per milliliter. However, a qualified donor's sperm density is required to be 60 million per milliliter, three times the normal density.

"A certain number of men have been rejected because of this," Tang said.

A nationwide survey found that in Shanghai, only 21 percent of donors have qualified sperm. Henan has 22 percent, and Beijing has only 15 percent.

Tang blamed smoking and alcohol consumption, which can have an effect on the quality of men's sperm.

And in order to avoid repeated sperm donations, which could lead to a lack of genetic diversity, every donor can donate sperm only once in his entire life.

"This requirement also limits the number of donors," he said.

Cheng and Yang had high expectations, hoping to find a sperm donor who was educated, handsome, about 1.8 m tall and not interested in drinking and smoking.

"We have completely given up these expectations. We just hope we can find proper sperm from a healthy donor, and the donor's blood type should be the same as my husband's," Yang said.

Donors should be between the ages of 22 and 45. According to sperm donation regulations, they should have no serious medical disabilities and a family background free from any known inherited diseases or disorders.

In addition, sperm banks recommend couples only accept sperm whose donors' blood types are the same as at least one member of the couple.

"Some of the couples may tell their children the truth about how they were born when they grow up, but most of the couples choose to keep it a secret," Tang said.

Choosing a donor with the same blood type can avoid confusion when the children grow up, he added.

Editor: Yan