In this case, you'd better choose some gifts that can directly show fatherly love. After he receives it, he can feel how sacred and wonderful it is to be a father, so that he will have the idea of starting a family.
Give personalized crafts; it's best to choose those crafts with intimate father-son shapes. For specific shapes, you can go to some more professional gift websites and ask some professional gift experts to help you with suggestions.
Give a life-like ceramic sculpture: Send your boyfriend's photo to a special gift shop. Ask them to make a real-life imitation ceramic sculpture. It's best if your boyfriend is holding a child, or holding a child, anyway, it should show the shape of fatherly love.