CANBERRA, Australia (AP) -- Seven-month-old Gammy, who was born with Down syndrome and a congenital heart condition, is being cared for by his young Thai surrogate mother after his Australian biological parents left him behind in Thailand, taking home only his healthy twin sister.Now the Australian government says it is considering intervening in the case, with the country's immigration minister saying Monday that the little blond, brown-eyed boy might be entitled to Australian citizenship.Pattaramon Chanbua, a 21-year-old food vendor who has two young children of her own, says she met the Australian couple only once, when the babies were born, and knew only that they lived in Western Australia state. The couple has not been publicly identified.Australian Immigration Minister Scott Morrison called Pattaramon \an absolute hero\ and \a saint