AIDS, or Auto-Immune Deficiency Syndrome is a condition that comes from HIV, or Human Immunodeficiency Virus, which is an STI. AIDS itself isn't an STI, but it is caused by one.
UTIs are simply infections of the urinary tract. It's like when you get a throat or ear infection. You can get it from having sex and irritating your urinary tract, or you can get it from getting soap in there, or from any other number of reasons. [ NinjaNeer's advice column | Ask NinjaNeer A Question ]
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