Claim: Fred Trump was 13 in May of 1918.
Evidence: Frederick Christ Trump -LRB- October 11 , 1905 -- June 25 , 1999 -RRB- was an American real estate developer and philanthropist , primarily in New York City , and father of Donald Trump , the 45th President of the United States , and Maryanne Trump Barry , a United States Court of Appeals judge.