Leukocytes are not limited to blood. They occur elsewhere in the body as well, most notably in the spleen, liver, and lymph glands. Most are produced in our bone marrow from the same kind of stem cells that produce red blood cells. Others are produced in the thymus gland, which is at the base of the neck.
Once your baby is past 3 months than that is no longer a newborn. But that isn't considered a toddler either yet. They are a baby up until they start to walk then they are called a toddler. Source(s): My opinion. chicken2008 Â· 6 years ago. Thumbs up. 0. Thumbs down. 0. Comment.
In the UK, babies stop being called babies because six is the age when they could (or should) be able to eat meals with both knife and fork. Infant is a subset of baby and goes up to around 3. In the UK in my day, babies are also infants but they stop being infants when they can walk on their own.