, his father could proudly (if he knew of it) proclaim he was the largest of the Kage's, as well as the fastest.
From what you have said til this point Hashirama would have been far larger than Minato. Hashirama was compared to being an Incarnation of Nature itself. In simple terms he was a self evolved Biju in Naruto terms and Avatar of a god in Asian terms. When he was 1 he would have been larger than Minato at his prime. THat was the difference between them...plus Hashirama could literally increase the size and hardness of his dick to the size of the Hokage Monument if he so wished.
Naruto is the only known child of a previous container of a Bijuu, let alone the Kyuubi's.
Tsunade's parent would have been one as well. Evidence is the fact they knew ahead of time KYUUbi's seal would weaken dangerously when she gave birth. That means previous case of that happening.