Is it good practice to give an empty instance to a method?

Question

C ++ is new here! There is a class Individualthat highlights a lot of memories, so we want to avoid copying. Let motherand fatherbe two Individuals. I would like them to reproduce using a method reproduceto make another one Individualcalled baby.

Intuitively, I would initialize babywith the default constructor, pass it in an argument reproduceand return the link (although, I suppose, there is no need to return the link). Here is the code that does this

class Individual
{
    public:
        void reproduce (const Individual& father, Individual& baby)
        {
          // Set all attributes of baby
        }
    private:
        // Plenty of variables
}

int main()
{
  // Do Stuff
    Individual mother(arg1,arg2,arg3);
    Individual father(arg1,arg2,arg3);
    // Do stuff
    Individual baby;
    mother.reproduce(father,baby);
}

Is this a good practice?

baby reproduce , , baby reproduce, .

class Individual
{
    public:
        Individual& reproduce (const Individual& father)
        {
            Individual baby;
        // Set all attributes of baby
        return baby
        }
    private:
        // Plenty of variables
}

int main()
{
  // Do Stuff
    Individual mother(arg1,arg2,arg3);
    Individual father(arg1,arg2,arg3);
    // Do stuff
    auto baby = mother.reproduce(father);
}

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Answer 1

- reproduce .

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Answer 2

Individual , Individual, :

class Individual
{
public:
    Individual(Individual const& mother, Individual const& father)
    {
        // Pass on traits.
    }
};

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Answer 3

:

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Individual baby;
mother.reproduce(father,baby);
if (baby.exists()) {
   // do stuff
}

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Individual* reproduce (Individual *father)
...
Individual *baby = mother->reproduce(father);
if (baby != nullptr) {
    // do stuff
}

bool reproduce (Individual *father, Individual * &baby) // or **baby
...
Individual *baby = nullptr;
if (mother->reproduce(father, baby) {
    // do stuff
}

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