The phenomenon, which is scientifically named heteroparental superfecundation, was described as extremely rare by her doctor.
Speaking to Globo, Dr Tulio Jorge Franco explained: “It is possible to happen when two eggs from the same mother are fertilised by different men. The babies share the mother's genetic material, but they grow in different placentas.”
It has been claimed that there are only about 20 other cases in the world where this has happened.
Local media reported that the children are now 16 months but Dr Franco only spoke about the case this week.
And now, one of the fathers looks after both children, giving their mother support.