BABY MAKES TWO Due September 16 (boy); Australia 193 posts
Apr 8th '13

It could be either because if you're period started on the 11th and it is regular you would've ovulated on the 25th and since you had sex on the 18th it is possible because sperm can survive for 5 days. My last period was on the 11th as well and I had sex on the 19th and I got pregnant.