Reproduction is a complex and delicate process, and it has been an eternal theme of human survival and propagation. Any abnormalities (genetic or acquired) in any part of the reproductive process can affect an individual’s reproductive ability, leading to the inability to conceive naturally. According to the “Research Report on the Status of Infertility in China” released at the 2009 Peak Forum on Infertility in China, the number of infertile patients in China has exceeded 50 million, affecting 10% to 15% of childbearing-age couples, making it one of the most impactful diseases. The emergence and application of assisted reproductive technology (ART) has provided new avenues for treating infertility.

Assisted reproductive technology refers to techniques that involve the manipulation of gametes, embryos, or genetic materials both inside and outside the body to create new life. ART involves multiple fields and disciplines, including obstetrics and gynecology, reproductive endocrinology, embryology, genetics, cytology, molecular biology, immunology, psychology, ethics, and law. ART can not only treat infertility but also be used to prevent the occurrence of genetic diseases. The widespread application of ART has made reproductive medicine a core of life sciences in the 21st century.

In a broad sense, ART includes two major categories: artificial insemination (AI) and in vitro fertilization-embryo transfer (IVF-ET) and its derivative technologies.

AI refers to the method of placing sperm into the female reproductive tract using artificial means to achieve fertilization and pregnancy within the body. Depending on the source of sperm, AI can be divided into artificial insemination with husband semen (AIH) and artificial insemination with donor semen (AID). AIH is mainly suitable for conditions such as male impotence, premature ejaculation, retrograde ejaculation, hypospadias, spinal cord injury, etc., where the sperm count and motility are within normal ranges or slightly abnormal; AIH can also be used for female reproductive tract anomalies, ovulation disorders, and immunological or cervical infertility.

AID is mainly suitable for conditions such as azoospermia, severe oligospermia, or genetic diseases in the husband, as well as blood type incompatibility or immunological infertility between the couple. Depending on the site of insemination, AI can be classified into intravaginal insemination (IVI), intracervical insemination (ICI), intrauterine insemination (IUI), intratubal insemination (ITI), direct intrafollicular insemination (DIFI), and direct intraperitoneal insemination (DIPI).

AI has a history of over 200 years and is the earliest applied assisted reproductive technology. In 1785, John Hunter from the UK successfully resolved the fertility issue of a hypospadias patient by injecting his semen into his wife’s vagina. In 1860, AIH was successfully performed at a hospital in New York State, USA. In 1884, William Pancoast from Philadelphia, USA, reported the first case of human AID. In 1953, Bunge and Sherman first reported successful artificial insemination using frozen semen, but it was not widely used until the mid-1970s. In China, AI technology was available as early as the 1940s, but only a few cases were recorded. In the 1980s, AI technology (including AIH and AID) gradually developed in some regions of the country.