The boys were born June 2, 2001, by Caesarean section to Sabah ... the globe in the past three years to separate twins joined at the head. Three were successful; one resulted in one twin dying ...

they were told two babies were conjoined and given counselling. Doctors said the 26-year-old father experienced 'a mixture of surprise and horror' followed by anguish when he first saw the twins.

Among the rarest of birth abnormalities, twins who are born joined at the head occurs at a rate of one in 2.5 million births. Only 25 per cent survive past birth. Here are a few noteworthy cases.

In the first place, twins occur when a fertilized egg splits into two or when two separate eggs ... Multiple babies are also more likely to be born prematurely, and generally require more care ...