I see he is not there.

The listing is the Civil Registration of births which has nothing to do with Baptism.

So what are the possibilities ?

The name, place or year are incorrect.

Unlikely to have been named if it was a still birth - what were the regulations at that time.

He was not registered - how faithfully were the regulations complied with.

He may have been registered in a different district - Peel and Douglas have yet to be indexed. I have run into the same problem with a Ramsey family. According to the 1901 census several of their children were born in Ramsey during the period but none show up in Registry.