Police are questioning two hospital workers, a day after 390 pieces of bone from newly-born babies or foetuses were found buried near a hospital in India.
India banned gender selection and selective abortion in 1994
Officers in the town of Ratlam, Madhya Pradesh, dug up a pit near a Christian missionary hospital after a tip-off.
Ratlam's police chief said they were investigating the possibility of female infanticide or illegal abortions.
Separately, the government announced plans to set up a network of cradles where unwanted baby girls can be left.
India's minister for women and child development, Renuka Chowdhury, told the BBC News website the cradles would be "everywhere". The babies will then be placed in homes.
It is the latest initiative to try to wipe out the practice of female foeticide and female infanticide.
In India, a girl child is often viewed as inferior to a boy. A bride's dowry can also cripple a family financially.
Ratlam's police chief, Satish Saxena, said a hospital superintendent and a sweeper were being questioned in connection with the discovery of pieces of bone.
"The question of female foeticide and infanticide is part of our investigation, as is illegal abortions," he told reporters.
Mr Saxena said it had been difficult to establish the number or ages of the newborns or foetuses concerned.
Local media reports said some of the pieces of bone, which included fragments of skull, had been found stuffed into plastic bags.
Police have sent the remains to a government laboratory in the state capital Bhopal, about 230km (140 miles) west of Ratlam, for testing.
The hospital has not yet made an official statement.
Research for the year 2001 showed that for every 1,000 male babies born in India, there were just 933 girls.
Research published last year estimating that the number of female abortions was as high as 500,000 a year was disputed by the Indian Medical Association.
In 1994, India banned the use of technology to determine the sex of unborn children and the termination of pregnancies on the basis of gender.
However, campaigners say many clinics still offer a seemingly legitimate facade for a multi-billion pound racket and that gender determination is a highly profitable business.
Experts say female foeticide is mostly linked to socio-economic factors.
It is an idea that many say carries over from the time India was a predominantly agrarian society where boys were considered an extra pair of hands on the farm.