There's no "may" about it, you go back your kids are gone.
Think about everything that would have to happen for you meet your spouse/mate at the right place and time, if you use your knowledge to make a boatload of money why would you both be working at that pizza place, and if you did meet her/him at the right time do they react differently to you if you're a millionaire?
You could warp back to the day your child was conceived and still things would turn out differently, you're mentally much older, and know a lot more bedroom tricks, know more about what she likes than you did first time around, so you climax an hour later than you originally did, she gets pregnant but you get a boy when you had a girl before or vice versa, even if the gender is the same maybe personality wise (or even looks wise) the kid is totally different. And nature/nurture comes into play. You parent differently than you did, change things you wish you could, kid turns out differently.
If you go full Biff, you're rich now, that's different schools, friends, vacations and experiences
Instead of 6 years old, you went back to the day your kid was born you could still end up with a completely different kid than the one you know