Legally or developmentally? Legally, it depends on your jurisdiction, however, by and large, children need the permission/approval of both parents to leave the general area of their home... To travel internationally, they need a passport and the consent of both parents, unless one parent has sole legal custody.
Brazil Entry Requirements Children under age 18 traveling alone, with one parent, or with a third party must have a notarized, written authorization from the absent parent or legal guardian. It must be translated into Portuguese and authenticated by a Brazilian embassy or consulate.
Brazil Minor Requirements Both parents must fill out and sign an “AUTHORIZATION FOR ISSUANCE OF BRAZILIAN VISA FOR MINOR” form. Applicants under 18 years old do not sign their visa application forms, as they are considered minors. Birth Certificate: Original or notarized certified copy of the birth certificate.
Children must usually have the same passport, visa or other international entry documentation required of adults. In addition, certain countries require children leaving that country without both parents or a legal guardian to have a letter of consent, in some cases notarized.
You need to have the consent of both parents to enter Canada. If you are traveling alone, you need a letter of authorization signed by both parents. If you are traveling with one parent, you need a letter of authorization signed by the nontraveling parent.
The letter of consent, preferably in English and notarized, from the other parent (if the child is traveling with one custodial parent) or signed by both parents (if the child is traveling with a guardian or alone) should say: "I acknowledge that my child is traveling outside the country with the name of the adult ...
If you have sole child custody, the other parent may not need to sign the Child Travel Consent. In this case, you should travel with a copy of your court custody documentation. In addition, if a child has a deceased parent, it's recommended to travel with a copy of the deceased parent's death certificate.
British-Brazilian dual nationals under the age of 18 who are travelling without both parents or legal guardians need authorisation from both parents or legal guardians to travel in Brazil or leave the country.
You need to have the consent of both parents to enter Canada. If you are traveling alone, you need a letter of authorization signed by both parents. If you are traveling with one parent, you need a letter of authorization signed by the nontraveling parent.
A consent letter demonstrates that children who travel alone, with only one parent/guardian, friends, relatives or a group (e.g. sports, school, musical, religious) have permission to travel abroad from every parent (or guardian) who is not accompanying them on the trip.