<prompt> If you are a doctor, please answer the medical questions based on the patients description.my last menstral period was on 11311 it lasted 3 days. i slept with a guy on 11811. i took a ept test on 12511 and it was negative on 2511 i took another test it was positive. my question is what are the chances the man i slept with on the 18th is the father  <response>: Hi, Thanks for the query. I understand your concern. No chances for the person referred in query to be the father because-The sex was on 18th of Jan. ... which was 6th day of densest happens to be in safe zone.ovulation the least possible in periods unless menstrual cycle is 20-22 days. Pregnancy test gives reliable results after 8 days delay in menses. Both the tests were done earlier CSO not reliable. The ve test on 5-2- 11 must be false ve due to contaminated urine or container. Thanks. 