The ultimate control is that over life and death, since those are the two things that we, as mere mortals, have absolutely no control over. There's no more helpless feeling as when you watch a loved one sicken and die. You stand there as they suffer and grow weaker and sicker day after day. As they grow closer to death your fear and helplessness increases until the inevitable time when you trade your helplessness for horror as they succumb to their illness and die.
Victor's mother's death was his first experience of loss, grief and mourning. He refers to the feeling as an "irreparable evil. The void that presents itself to the soul." When a loved one dies it does feel like a huge gaping hole has been torn from your chest leaving a huge painful void. Birth, on the other hand, feels like something warm and bright and hopeful is filling your chest.
Maybe Victor tried to fill the void in his soul with the bright warmth of new life when he obsessively built his creature. With the loss of his mother's love and adoration, perhaps he thought the creature would love and adore him for granting him life. Instead he learned many things, such as bringing a new life into the world doesn't guarantee that person will appreciate you and being able to control life and death wasn't the glorious achievement he had hoped it would be.