the boring answer is that there isnt any real reason for it yet. if you want to check if its with a love interest you can just open the spoiler section of the stat menu. i think when you deliver it even straight up tells you with whom the child was made.when you implement pregnancy into game why you don't implement mechanic to identify "father"?
it just says "it's positive, but would that be?" i am VERY interested to find answer to this question