Played Straight: Alice and Bob have a one-night stand. Alice finds herself pregnant, but Bob is completely out of the picture.
Exaggerated: Bob has several children, by several different women, whom he never again contacts or pays child support money to. In fact, he is always on the move, changing his name, so that the mothers of his children won't be able to find him.
Inverted: Alice becomes pregnant, and Bob marries her.
Alternatively, after the baby is born, Alice is nowhere to be found.
Subverted: Alice becomes pregnant, and Bob stays with her.
Double Subverted: But then they have a fight and break up, and Bob never contacts Alice again or sees his child.
Deconstructed: Children can certainly be raised by just one parent, but it's always better if they have another positive role model and caregiver. It is also more economically practical that way.
The child (and possibly Alice) is(/are) resentful of Bob's absence.
Reconstructed: Even if Alice and Bob don't stay together, Bob finds a way to be an active part of his children's life.
Alternatively, Alice marries Carl, who is more of a dad than the kids' biological father.
Alice raises the child alone. She has the financial means to provide for it without anyone else's help, and she raises a well-adjusted, healthy, happy child...all on her own.
Parodied: Bob is surprised to find out that he even has a child.
Bob gets Alice pregnant. They haven't even had sex.
Lampshaded:
Averted: Bob has no children by any of the women he's slept with.
Bob gets Alice pregnant, but does not leave her or the child.
Bob didn't sleep with Alice, therefore if she is pregnant, it's not his.
