HIV can be harsh on children. They are more prone to infections than the the rest of their peers. In addition, it can cause growth problems, motor skill problems (such as walking, crawling etc.) and mental issues (such as development of speach). Without antiretroviral treatment, 60-75% of children will die before the age of 5. 20% of children will develop serious illness in the first year of their lives. With treatment, the death rate drops below 20%. Babies born to HIV positive mothers will always test positive for up to 18 months because they carry their mothers antibodies. This does not mean they are infected (most aren't) so one way doctors will test a baby born to an HIV+ mother is through PCR testing (tests for the virus itself). I am not a doctor, but I have gotten this information from reputable sources.