Why is the birth rate so high in Brazil?

Brazil has a huge population because the enourmous country Brazil is, but there only live about 23 people per square km. You´ll maybe think that´s very little amount for cities like Brasilia, Rio de Janeiro etc... but for example in the Amazonas very little people live there. Less than 2 per square km this does that only life 23 people estimately per square km. The main reasons are because the weather and that people want to visit places like Brasilia, then they like it stay there and form a huge family which increases the population