Service aboard a Norwegian navy torpedo boat has been linked to an increased risk of having children with birth defects, a study says.
Some 114 children were born to parents who worked on the torpedo boat
Researchers looked at data from 2,000 personnel, the Occupational and Environmental Medicine journal said.
Bergen University found those serving in the 1990s on the boat used in electronic warfare had four times more risk of having children with defects.
But the team were unable to identify the reason for the results.
The Royal Norwegian Navy commissioned the researchers to do the study after reports surfaced of people of military personnel having children with birth defects.
The KNM Kvikk, which was in service between 1971 and 1995, was a torpedo boat which was used for electronic warfare.
Between 1987 and 1994 the ship was fitted with a 750 watt high-frequency transmitter designed to block communications between enemy vessels, but apart from that had similar communication and radar equipment to that of many vessels in the navy.
The team found that of the 114 children of parents who had served on the ship, eight had been born with birth defects and six were stillborn. The problems were four times the rate of those among children whose parents did not serve on the ship.
Researchers were unable to say that the radiation from the transmitter had caused the birth defects as other factors such as stress and exposure to vapour from oil or diesel could play a role.
The Ministry of Defence in Norway said an inquiry has been launched into the issue, which has prompted compensation claims.
Since the mid 1990s Norway has signed up to a Nato agreement to ensure people keep to safe distances from such equipment.
An investigation carried out in 1999 concluded no causal link could be established between the high-frequency transmitter and birth defects.
Lead researcher Dr Nils Mageroy said: "It is clear the children of people who served on board the ship had higher rates of congenital malformation.
"However, what we cannot say is that the transmitters were the cause. Other factors could have had an impact."
Dr Michael Clark, of the UK's Health Protection Agency, said the 750 watt transmitter was as powerful as a microwave.
He added: "We will look at this study carefully. The military are major users of radio and radar but, as the journal points out, this study does not actually establish a link between exposure and birth defects. Other studies have shown no link."
The UK Ministry of Defence said it was unaware of any similar cases among British military personnel.
Heidi Langvik-Hansen, of the Norwegian Ministry of Defence, told the BBC News website a register had been set up to improve surveillance of the health of armed forces personnel in the country.
"Information from this register may be linked to civilian health registers for general studies and comparisons on different aspects of the health situation for military personnel, compared to the population as a whole."