Yep. If you want to retire on a 401k alone, you have to start putting money in it as close to the day you are born as possible.

If I get to have a kid I'm opening them a Roth IRA and putting all the money that I possibly can into it.

$10,000 on the day they are born would be somewhere in the $250,000 - $1,000,000 range (depending on whether they average 5% or 7%, and if it were to average 10% it would be $6.47 million at age 65), assuming no further investments were made on it and that there were no management fees attached to it, and that somehow they could resist the temptation to draw down from it early to buy a house or pay student loans, cover debts, etc..