Do I need to put my dads details on my passport?

[makeloveyourgoal]

Applying for my very first passport. Not had anything at all to do with my dad since I was 3 years old. The passport form asks for my fathers details, if known. I do know them, but would rather not put them on [personal reasons]

Will it make any difference if I don't put them on?

If he's on your birth certificate, yes. If not, no.

Yes, he is on birth certificate.

It's just to ensure that your information ties up correctly - nothing to worry about. (If you're an adult, he wouldn't be notified or anything.)