How to fix "Debug Error!, Stack around the variable 'x' was corrupted"?

I am really new to C-language and was testing a simple if-statement program which, from your age and gender tells one answer from 4 different outcomes.

Which goes something like this: If you are under the age of 55 and are male, it will print: "You are a man at his best age!"

But I come across a error code which says: Run-Time Check Failure #2 - Stack around the variable 'miesVaiNainen' was corrupted.

I myself, think it might have something to do with: if (miesVaiNainen == "n" && age <= 55)

How can I fix this issue so the error wont come across?

I've tried to look for help in stackoverflow and tried to change the code a lot.

    int age;
    char manOrFemale;

    printf("Are you a man or a female(m/f)");
    scanf("%s", &manOrFemale);

    printf("Input age:");
    scanf("%d", &age);

    if (manOrFemale == "f" && age <= 55)
    {
        printf("\nYou are a lady at her best!");
    } else if (manOrFemale == "f" && age >= 56)
    {
        printf("\nYou look young for your age!");
    }


    if (manOrFemale == "m" && age <= 55)
    {
        printf("\nYou are a man at his best age!");
    } else if (manOrFemale == "m" && age >= 56)
    {
        printf("\nYou are a wise man!");
    } else {
        printf("There has been an error in the program!");
    }
}