After the new body has separated from the parent, Primus will imprint his designs on the new body, giving it a mind, a body form, and an alternate mode. As seen with Lord Jhiaxus. Primus, a defender of order and the sentient core of Cybertron, can create a new Transformer from the body of the planet. This process is identical to the 'budding' process. When finished, the creator and the creation have a relationship similar to that of a parent and child.
Transformers built by the same creator are like siblings.
This usually results in the creation of offspring. The child first manifests itself as a small glowing sphere, like a miniature Vector Sigma, nested beneath the chest armor of the mother. The child, unless provoked, stays there until a body is built for it. These bodies are generally smaller than normal, about Micromaster-sized. There have also been mentions of 'growth stages', which I assume mean exchanging one's present body for a more physically mature one.