It can be inferred that they are talking about a daughter due to that it is common in Spanish to talk about "hijo-hija única"when referring to an only child. In this case Marisol would be the Carlos and Lucia "only daughter"
Lo que suelo hacer los sábados es despertarme y tomar una ducha, luego me lavo la cara. cuando me lavo la cara, me pongo algo de ropa. quiero ir al cine con mis amigos este sábado
