I think one of the points your teacher may be making is the importance of the responsibility parents have to nurture their children, to teach them what they need to know to get along in the world. The monster's deepest tragedy was that after Victor Frankenstein created him, he abandoned him, leaving him to fend completely for himself. Not only did the monster have to develop a sense of who he was and learn the intricacies of human relationships completely on his own through books and observation of the family at the cottage, he also lived with a lifelong rage which resulted from being left alone in the world. A correlation may be drawn between the monster's experience and children in our own society who have not been properly nourished by their parents, and possible tendencies toward violence other and maladaptive behaviors which may result from their abandonment.
There is a very good reason your teacher keeps talking about this. Let me outline some things for you:
1. Mary Shelley's own mother died from complications of giving birth to her. 2. There are lots of parent-child relationships in the book. To name a few: Caroline Beaufort (Frankenstein) and her parents, Victor and his parents, Elizabeth and her childhood, Justine Moritz and her childhood, Safie and her father, Felix and Agatha and their father, Adam and God, and of course, the Creature and his "father". 3. The underlying message that Shelley is trying to get across is this:
If you are going to bring a child into the world, you have to take responsibility for that child. Clothing, food, shelter, education, and love are among the necessities.
The Creature is denyed all of this, and as a result, he feels angry and abandoned. (Not unlike the feelings Mary Shelley had growing up without her mother.)
The parent-child relationship is a very important theme in the book, and understanding the message Shelley is sending will shed greater light on her message of unconditional love. Had the creature been given this basic element, things would have turned out very differently for everyone.
Shelley is pointing out that Victor had a wonderful upbringing with loving parents, yet is not able to parent his own "child". Victor neglects the creature he created, yet in stark contrast to this example, Caroline Frankenstein had a lovely, close relationship to her stepdaughters. This is to show that biology does not have to play a role in parenting.