[@Weird Tales]
Ah
Well all I've found on it so far is this:
"Though theoretically possible, as Titans can take on human form, there is no known of instance of a male or female Titan having a "demititan" child with a mortal."
http://demigodshaven.wikia.com/wiki/Titan

Which means both yes and no
Yes they could technically have one
But no because they never did....they probably wouldn't want to either but that's my opinion on a myth

Edit: so I believe that settled it