"She can start a family."
Translation:Ella puede formar una familia.
"Start a family" is the most common way to express it in English. "begin", "form", "iniitiate", "create", "have a" etc. are all possible but not as clear, and in some cases may be misleading. Same in spanish, it's a question of what the common usage is that expresses the idea. If it is "formar" then that is what it is, and I just have to learn it.