Portuguese has two different words for baby: bebé in Portugal and bebê in Brazil.
The word was brought from French bébé; while the Portuguese took the accent at face value (keeping the same accent from French, but applying Portuguese rules to the accent, therefore making the e an open vowel), Brazilians decided to keep the phonetics intact (since the acute accent in French is used for the exact same purpose as the circumflex in Portuguese: to close a vowel).
Also of note: [o/a] bebé is used as a two-gendered noun, meaning you should refer to a baby girl using a bebé and a baby boy via o bebé (like most other nouns that work like this, the masculine is the go-to gender when you’re not aware of gender or you’re talking about babies in general; if you’re talking about something that refers solely to baby girls, use the feminine instead). Portuguese is still a bit behind when it comes to adapting the language to non-binary situations (the masculine gender being used in generic descriptions of professions is an important issue, and so is the lack of third gender pronouns and signifiers)
Compare this with [a] criança (child), which is always feminine regardless of the actual gender of the child.
- [o] berço: crib/cot
- [o] leite: milk
- [o] nascimento: birth