If you're asking how it detects pregnancy, it does so by having a chemical dye that reacts with the hormones that are present when pregnant. If you're asking how it gives a negative result and then...
Depends on where you are at in your menstrual cycle and if he actually got semen into your vaginal tract far enough. I would advise a pregnancy test.
Answer .
WELL DEPENDING ON YOUR CYCLE YOU CAN...
A male can get as many women pregnant as he is able to have sexual intercourse with in a day, week, month, or year. Some men end up having children who are the exact same age, born on the same day of...