The first test-tube, or in vitro fertilization, baby was Louise Brown, who was born in the UK in 1978 -- seen here holding her twins. Reuters

Five million test tube babies have been born since the practice was first introduced in 1978, researchers said on Monday.

The first test-tube, or in vitro fertilization (IVF), baby was Louise Brown, who was born in the UK in 1978.

Sadly, her mother Leslie Brown died last month.

The milestone was announced at the European Society of Human Reproduction and Embryology conference in Turkey, the BBC reported.

The delegates said the 5 million baby marker represents official figures up to 2008 plus estimates for the three years up until 2011.

This technology has been highly successful in treating infertile patients. Millions of families with children have been created, thereby reducing the burden of infertility, said Dr. David Adamson, chairman of the International Committee for Monitoring Assisted Reproductive Technologies, or Icmart.

The technology has improved greatly over the years to increase pregnancy rates.

According to Icmart figures, roughly 1.5 million IVF procedures are performed every year, with around 350,000 babies born through the process.