Sure,I think you can.
Wow! I cannot believe that you are of an age that you might have stomach ulcers and don't know how pregnancy works. Okay, here goes... IF YOU ARE HAVING SEX YOU MAY BECOME PREGNANT... Okay that being said you can do a lot to mitigate problems with protection and birth control. There are no diseases that really prevent pregnancy however, although they may make it more difficult to become pregnant or to bring a child to term. Your stomach has nothing to do with reproduction, other than to keep you alive so that you can reproduce, provide energy to produce eggs, provide energy for a growing baby etc. Even if you have oral sex, you can't get pregnant with ulcers LOL...