“Test-tube baby” is a slang term applied to a baby conceived through in vitro fertilization (IVF), where an egg is fertilized with sperm outside of the body in a laboratory setting, and the resulting embryo is then transferred to a uterus.
This term originated in the mid 20th century, when the assisted reproductive technology (ART) was initially developed to treat infertility.
FertilitySmarts explains Test-Tube Baby
The first child born as a result of IVF occurred in 1978. Originally, the treatment was considered controversial. However, since that time, IVF has become a leading treatment for infertility, and over 5 million children have been born as a result. Robert Edward, the scientist credited with developing IVF, was awarded a Nobel Peace Prize in 2010.
Test-tube baby may be considered an offensive to individuals who feel that the term enforces a perception that the conception of a child through ART is "unnatural" or somehow lesser than a child conceived through intercourse.