"Hermanos" means both "brothers" and "siblings". How do you know which is meant?
In Spanish, "male" terms are used to refer to collections of male elements but also to refer to collections of both male and female elements.
If you ask "¿cuántos hermanos tienes?", you can be asking "how many male siblings do you have" or "how many siblings do you have". Which one are you using depends on the context, but that kind of situations can be confusing in real use.
An equivalent situation happens in English when you say "You are good" to someone in a group. Are you saying that the group is good, or that the person is good?
This occurs since the translator does not discriminate between register.
When it comes to saying ¿Cuantos hermanos tienes?, this includes both male and female; however, depending on the emphasis we want to show, you can also say ¿Cuántas hermanas tienes? to reveal the quantity of females.
Suggestion: do not use translators to learn Spanish.