Major League history is filled with prodigious bloodlines. Some, like Barry and Bobby Bonds, featured two generations of stars, while other families like the Bells, Boones and LaRoches, seem to have enough Major League players in their families to field their very own teams.

But despite the 140-something years of Major League Baseball and the thousands of players to have put on a jersey, only two father-son duos have ever taken the field at the same time. Long before Tim Raines and Tim Raines, Jr. accomplished it in Oct. 2001, Ken Griffey Jr. and Sr. did it for the Mariners on Aug. 31, 1990.

Which, when you think about it, is absurd. Here are all the things that need to go right to make this happen (at least until medical science replaces us all with robots):

- The father has to be a Major League player

- And not just a Major League player, but one who is good enough and remained healthy enough to be a viable big leaguer for decades.

- Who has a son that is also talented enough to be a Major Leaguer

- And not just good enough, but a phenom, ensuring that they reach the Majors and are successful at a very young age.

- And if all of those conditions are met, the team would need to have a need or opening at two positions to fit both the elder and younger on the team at the same time.

Fortunately, the Mariners were able to do it in 1990 -- when Griffey was just 20 years old and coming off his first All-Star appearance, and Ken Griffey Sr. was 41 and in his second stint with the Reds. Even then, though, it wasn't entirely easy. Griffey Sr. first had to deal with his Reds contract.

On Aug. 18, Griffey Sr. was given 15 minutes to decide if he wanted to retire, accept his release, or be placed on the disabled list by Reds GM Bob Quinn. Thinking that retirement would let him move to the Mariners, Sr. chose that option before learning that there was a 60-day waiting period before a retired player could sign with a new team. Sr. then had to "unretire," accept his release and pass through waivers before the Mariners could sign him.

See? Nothing is easy.

Fortunately, once he was picked up by the Mariners, he and Jr. got off the mark pretty quickly. Taking on the Royals on Aug. 31, Sr. found himself batting second in the lineup with Jr. directly behind him. Facing Storm Davis with one out in his first ever Mariners at-bat, Sr. laced a single back up the middle before his son hit a ground ball single to right one batter later.

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Not only were they the first father-son team to ever be in the same lineup together, but they were the first father-son duo to be on the basepaths together. Both would even come around to score later in in the inning as Seattle went on to win, 5-2.

Griffey Sr. said after the game:

"This is the pinnacle for me, something I'm very proud of. You can talk about the '76 batting race, the two World Series I played in and the All-Star Games I played in. But this is No. 1. This is the best thing that's ever happened to me."

He would go on to say about his relationship with his son-turned-teammate, "We've become more like brothers over the last four or five years. He's asked me for a lot more advice than he's ever asked before."

Though the two would only share a month together in the big leagues, they had at least one more highlight together: When the father-son duo hit back-to-back jacks.

They wouldn't be in the lineup together again, but there were plenty more years together in uniform. Sr. was a coach with the Reds when Junior joined the team in 2000 and the pair were reunited once again with Team USA at the World Baseball Classic.

Now, I don't want to pressure anyone into the biggest decision of their life (at least, after "Should I DVR the 'Welcome Back Kotter' marathon?"(yes)), but if any of the young rookies currently tearing up the league wouldn't mind having children soon, so that 20 years from now we can see another family reunion on the field, that would be great.

Correction: This story originally stated that the Griffeys were the only father-son duo to ever play together. The piece has been updated to reflect that Tim Raines Sr. and Jr. also accomplished the feat.