The fallopian tube is a tunnel which will be passed by the sperm on its way to the egg.
This might be possible if all the sperm does is pass by the entrance to the tunnel without actually entering it. But then it won’t be on its way to the egg, it will be on its way somewhere else!
If you want to say that the sperm enters the tunnel, travels along it and then meets the egg, you need to use a preposition that carries that meaning:
- The fallopian tube is a tunnel which the sperm passes through on its way to the egg.
Compare these situations:
- A > B: The sperm passes through the tunnel.
- C > D: The tunnel is passed by the sperm.
- D > E: The tunnel is passed by the sperm.