The lightning round is supposed to last thirty seconds for each team, but the boys' round lasts over forty and the girls' almost sixty.
During the coin toss scene, the table is rotated 90 degrees clockwise in one of the reaction shots, compared to its placement in the rest of the scene.
Phoebe in previous episode said she didn't believe in gravity but in the scene when she sits in the armchair she says ''I'm going to let gravity, you know, do its job''.
When Monica, Rachel, Joey, and Chandler are playing the game, Ross says that each team needs to answer 10 questions. There are 32 questions on the board. Both teams are tied after the 1st round is over. At that point, there are still 12 questions left on the board, but when they start the speed round, there are 13.
At the end of the first round of "Who Knows Whom?", there is one unpicked question in the boys' It's All Relative column. However, a later shot shows two unpicked questions there.
Phoebe couldn't have found out if she was pregnant already because it takes about 9-11 days after the transfer for the doctor do a blood test to find out if she is pregnant. They also don't recommend doing a home pregnancy test after IVF.
Ross explains the rules of the game by saying "each team will answer ten questions. The first team to answer the most questions, wins." He should have said "The team that answers the most questions, wins." In Ross' explanation, the game would have been over after the men get the first question correct.
[Edit] Incorrect. What Ross meant, was: if one team has already achieved more answers than the other team could achieve in 10 rounds (e.g. it's 6:0), then they win.
Considering that Ross is both a scientist and a parent already, it makes no sense that he doesn't know how the doctors will know whether Phoebe is ready or not for embryos implantation.
Correction: Ross is a paleontologist - completely different field of expertise to anything medical related. Physicists are scientists too, would they know how a surgery works?
By that point, Ross is a parent by accident. Ben wasn't born due to "trying to get pregnant", something that would have urged him alongside Carol to educate themselves on the details of conception.
While the friends are moving to each other's apartments, Phoebe is seen playing her guitar ("Are you in there, little fetus?"). However, when Phoebe arrived at the apartment, she did not have her guitar with her.
When Phoebe goes to take the pregnancy test that Frank and Alice got her, she is only in the bathroom for about 35 seconds before coming out and telling everyone she's pregnant. 35 seconds isn't enough time to take the test while also having it produce a reliable result (considering most pregnancy tests make you wait for around 2 minutes before checking).
Several of the grocery items that Rachel buys are a Safeway brand (the soda and cookies), and there aren't any Safeway stores in New York.
Near the end of the episode, just before Monica and Rachel find something scary in a drawer in their "new" apartment, the boom mic is visible at the top of the frame during the wide shot.
When Rachel first says that she won't move, Monica sticks up for the deal by saying "If we had lost, we would've made them get rid of the birds." What she meant to say was "If they had lost..."
Dr Zane tells Phoebe, Alice, and Frank Jr that they need to implant five embryos to ensure a 25% chance of pregnancy. Implanting more than two embryos does not increase the odds of having pregnancy - it only improves the chances of a multiple pregnancy, which is exactly what happens later. A specialist in in vitro fertilization should have known better.