Why using a pointer of a self-defined structure in the CS50 Inheritance problem

Question

Hi here is the link of the homework description. And here is the part of the code that's relevant:

typedef struct person
{
struct person *parents[2];
char alleles[2];
} person;

const int GENERATIONS = 3;

person *create_family(int generations);
void print_family(person *p, int generation);
void free_family(person *p);
char random_allele();

Please help me understand why we want the return value ofcreate_family(int generations) to be a pointer, not just a variable person. What's the advantage of using pointer here?

I speculate that's because it's more efficient, as we can free the memory as we go, but I'm not sure.