Yes, a baby can have two last names, and this is known as a double-barrelled surname or a hyphenated surname. The practice of giving a child two last names has become increasingly popular in recent years, and it is recognized in many countries around the world.

In some cultures, such as Hispanic or Latino cultures, it is common for a child to be given two last names. The first last name is typically the father’s last name, while the second last name is the mother’s last name. This practice is known as the “apellido materno” or the mother’s surname, and it is considered an important part of a child’s identity.
In other countries, such as France and Germany, it is also common for children to be given two last names. In France, children are typically given their father’s last name as their primary surname, but they may also be given their mother’s last name as a secondary surname. In Germany, children may be given two last names, with the first last name being the father’s last name and the second last name being the mother’s last name.
In the United States, there is no legal requirement for a child to have a single last name. Parents may choose to give their child a double-barrelled surname, but it is not recognized in all states. Some states require that the parents of a child choose one last name to be the child’s legal surname, while other states allow parents to choose a hyphenated last name or to use both parents’ last names without a hyphen.
In Canada, children may be given two last names, with the first last name being the father’s last name and the second last name being the mother’s last name. However, the second last name is not recognized as a legal surname unless it is hyphenated with the first last name.
There are some potential drawbacks to giving a child two last names. One of the biggest challenges is that the child may have difficulty with legal documents, such as passports or driver’s licenses, if the names do not match exactly. Additionally, hyphenated last names can be difficult to spell and may be prone to misspellings or errors.
Overall, giving a child two last names is a personal choice and can be a meaningful way to honor both parents’ surnames. However, it is important for parents to consider the potential challenges and drawbacks before making a decision. Parents should also research the legal requirements in their country or state to ensure that they are following the proper procedures for naming their child.