Just did a quick google and found this... Not that it matters either way as they are and will always be loved to bits I guess it would just affect decisions like the vaccination Q etc etc
"Very young kittens may occasionally show "false positives" for FIV, because of the transfer of antibodies from a mother cat in the womb. It is suggested that these kittens be tested again at age 6 months. On the other hand, a negative FIV test will indicate a strong possibility that the kitten does not carry the virus."
and this... (taken from
http://www.gla.ac.uk/companion/ofiv.htm#kittens )
My feline immunodeficiency virus (FIV) infected queen has kittens - will they be FIV positive?
FIV does not generally cross the placenta to the unborn kitten. There is a small possibility of an FIV positive queen infecting her kittens as she bites through the umbilical cord. The test for FIV is an antibody test, cats which are FIV positive have antibodies in their blood. Queens pass antibodies to their kittens in their milk, especially in their first day of life, so that kittens of FIV positive queens can have positive FIV tests, although in fact they are not themselves infected - because of the antibody from their mothers milk. So it is essential that kittens of FIV positive queens are not FIV tested until they are at least 16 weeks old, by which time the antibody they got from suckling should have disappeared. If you really can't wait until they are 16 weeks old to know whether or not kittens are FIV positive, it is possible to do a virus isolation test, though it requires quite a big blood sample for a little kitten to give. Isolating the virus will cost rather more than the routine antibody test.
Kittens which have FIV positive tests are usually not FIV infected. They should be retested after 16 weeks of age.