"Bracha" or "Bechira?"
To answer this question, we must differentiate between two basic types of blessings found in Sefer Breishit. For the sake of convenience, we will refer to one as bechira and the other bracha. Let's explain:
We use the name bechira (selection) to describe God's blessing of "zera v'aretz" to the Avot, i.e. being chosen to become the forefathers of His special nation. Bechira implies that only one son is chosen, and that all other children are rejected. As we explained above, this process began with God's choice of Avraham Avinu and continued with His choice of Yitzchak over Yishmael. It is not clear, however, when this bechira process will end.
We will use the name bracha to describe a blessing of personal destiny (e.g. prosperity, power), given by a father to his sons. For example, Noach bestows a bracha on each of his three sons (9:24-27). He does not choose one son to become a special nation. Rather, he blesses (or curses) each son based on his potential.
The classic example of bracha (as opposed to bechira) is found in Parshat Vaychi when Yaakov Avinu, prior to his death, blesses each of his twelve sons (see 49:1-28). In those blessings, Yaakov is not choosing which of his children will become God's special nation. Rather, he bestows a blessing of personal destiny on each son, according to his understanding of each son's character and potential (see 49:28).
Thus, according to these definitions, bracha is typically bestowed by the father, while bechira is bestowed by God.