A record 9,211 babies were born in Japan through reproductive technology such as in vitro fertilization in 1997, officials at the Japan Society of Obstetrics and Gynecology said Wednesday.

The number, up 1,801 from the previous year, brings to about 36,000 the number of babies conceived through such procedures since their introduction in 1983, the society said.

Rapid growth in the use of microscopic fertilization by couples seeking infertility treatment helped boost the overall figures, the officials said. Microscopic fertilization, in which sperm is transferred to the ovum using a hollow needle under a microscope, is one type of in vitro fertilization.

Also contributing to the rise was a profusion of new facilities conducting microscopic fertilization, with the number of facilities employing the technique rising from 106 in 1996 to 145 in 1997, the officials said.

The committee sent questionnaires to 394 clinics registered with the society as being capable of carrying out in vitro fertilization and received 360 responds.