Okay so i'm Stephanie and i have a friend of 15 years named Jill. we are both 19 now and as of recently about a year ago her and my brother started dating. my brother is 25 and just so everyone knows i was completely okay with it since day 1. Jill recently went to the doctor for a yeast infection and the doctors told her that they found traces of chlamydia. Jill went for her annual around the same time that she first started having sex with my brother which was about after a week and a half and was tested for stds and everything came out negative. noting that they had sex multiple times within that period and it was unprotected. and during some time in their relationship they had a "break" for about a week. my brother swears up and down that he must have had chlamydia when they first started having sex and didn't know. i myself have had chlamydia and had no symptoms for months but only found out because my partner at the time ended up having symptoms. but if she got tested after a week and a half and everything came out negative i believe based off of my own experiences and from what my doctor has told me in the past, that it should have shown up for her when she originally got tested