On board Titanic there were 17 women that were known or likely to be pregnant.
Two of those women died in the sinking.

It was common for men to leave their pregnant wives ashore. A total of 55 men became fathers after their deaths on April 15, 1912.

The most famous of them was John Jacob Astor, whose son was born on 14th August 1912.

There were many other passengers and crew members who never had the chance to get to know their children.
This includes Henry Morley, who was proven to be the father of Kate Phillips daughter, Ellen, only recently on a Titanic Connections live stream.

Source: Encyclopedia Titanica (see the whole list with the 55 men here)