Sudden infant death syndrome (SIDS) can be common in both male and females and has precious little do with the gender difference as believed earlier, new research has revealed.

SIDS is considered more common in boys than girls. About 60 percent of infants who die from SIDS are male. But the new study conducted by the researchers at the National Health and Medical Research Council of Australia suggests that gender differences or levels of wakefulness are not to blame.

Infant boys, however, are more easily aroused from sleep than girls, the researchers found after conducting studies in 50 healthy infants. A technique of blowing a puff of air into the infants' nostrils is often used to wake them up from sleep.

They found that the strength of the puff of air needed to arouse the infants was much lower in males than in females at two to four weeks of age. This difference was no longer significant by ages two to three months, when SIDS risk peaks. The researchers also found the frequency of arousals similar for girls and boys at both ages.

"Since the incidence of SIDS is more in male infants, we had expected the male infants to be more difficult to arouse from sleep and to have fewer full arousals than the female infants," says senior author Rosemary S.C. Horne, a senior research fellow at the National Health and Medical Research Council of Australia.

"In fact, we found the opposite when infants were younger at two to four weeks of age, and we were surprised to find that any differences between the male and female infants were resolved by the age of two to three months, which is the most vulnerable age for SIDS," she says.

The failure to rise from sleep is usually the fatal pathway to an infant dying suddenly and unexpectedly, says Horne, who is also deputy director of the Monash Institute of Medical Research in Melbourne.

Perhaps, the reason behind the slightly increased ration of SIDS in boys could be that parents are known more often to try to calm restless male infants by putting them to sleep on their stomachs. Placing babies on their back to sleep reduces the risk of SIDS, the researchers say.

"Our study has highlighted the fact that SIDS is multi-factorial and that at present it is not possible to predict the deadly combination of internal and environmental factors that will results in SIDS," says Horne.

Therefore, parents should be aware of the known risk factors and avoid them as best as possible by practicing the safe sleeping guidelines of sleeping babies on their backs, making sure their heads cannot be covered by bedding and keeping them free from cigarette smoke both before and after birth, she suggested in the research report published in the science journal Sleep.