i think tat rose could hav had a child from jack. they did hav sex didnt they. it couldve happened. if so, tat would be so cool. also if he didnt die they would hav gotten married anyway b/c in the end wen the carapathia was pulling into the dock in ny, wen the crew member wanted to take her name they said...

"can i take ur name, love?" said the crew member

"rose, rose dawson." said Rose

"thank you." said crew member

and last time i check jack's last name was dawson!!!!!!!!!!!!