Why is it printing twice?

Question

After the user enter his weight for the first time it prints twice the choose gender line while i only want is to be printed once.

#include <stdio.h>

void main()
{
    float weightMen = 0, weightWomen = 0, temp = 0;
    int counterMen = 0, counterWomen = 0, i;
    char choice = ' ';

    while (temp != -1)
    {
        printf("Please choose your gender,\nM - for men\nF - for women\n");
        scanf_s("%c", &choice);

        if ((choice == 'M') || (choice == 'm'))
        {
            printf("Please enter your weight:\n");
            scanf_s("%f", &weightMen);
            temp = weightMen;

            if (temp == -1)
            {
                break;
            }
            else
            {
                weightMen += weightMen;
                counterMen++;
            }
            
        }
    }
    printf("%.2f", weightMen);