Factual error: Dr. Eve Russell seems to be a "jack of all trades" in the medical profession, but it's impossible for her to know everything about every medical condition. When Theresa is going to marry Ethan, she goes and gets birth control pills and takes her first pill the day before the wedding. That night they make love. The next day, the wedding never takes place and Theresa flies off to find Julian. She forgets her second pill and sleeps with Julian. Eve tells her that since she didn't take a pill before sleeping with Julian then the baby is his. Any doctor would know that (and also suggest that) birth control pills are not completely effective until a person has been taking them for at least seven days, and a secondary form of birth control should be used. There's no way that Theresa's just taking 1 pill would protect her from being pregnant by Ethan, and this would still warrant a paternity test.
Factual error: On 4/5/07, Chad had a flashback to when he met Vincent at a gay bar, over a year earlier. The song playing in the bar was Pink's "U + Ur Hand," which came from a CD that wasn't released until months after the scene took place. That particular song wasn't released as a single until about an additional year later.
Factual error: On 5/18/06, it was simultaneously breakfast time in Rome, Italy, and in Harmony, Maine. But since Rome time is six hours later than Harmony time, this is impossible. Breakfast time in Harmony is lunch time in Rome, and breakfast time in Rome is the middle of the night in Harmony.
Factual error: Clarice's actions are not in keeping with America's actual child welfare system. Clarice came to Theresa's house to remove Little Ethan on 12/09/03, which in the show was the day after Rebecca claimed Theresa was neglecting the child. There was no investigation of any kind. In a real case of possible child neglect, the home is visited and the family situation is thoroughly investigated before any action is taken.
Factual error: In the spring of 2006, Whitney traveled from Harmony to Rome, and we are left to assume that she flew. After Whitney had arrived in Rome, Chad and Simone found out and went to Rome to find her. Paloma and Jessica accompanied Simone. After Paloma arrived in Rome and got into some trouble, Theresa and Ethan found out about it and went to Rome as well. So there were three consecutive trips from Harmony to Rome, and they all happened during the same night; Whitney left after dark, and Theresa and Ethan arrived in Rome the following morning. But each flight to Rome should take six hours, and there is a six hour time difference, which adds up to a full twenty-four hours. So nobody who left Harmony at night could have arrived in Rome before morning. And Theresa and Ethan should have arrived in Rome after dark on the second day, not first thing in the morning.
Factual error: On 7/29/05, the men at the Tsunami Warning Center talked about the tsunami that was heading towards Harmony, and then the scene shifted to a giant wave. However, the shot was of a large, cresting ocean surface wave. Tsunamis are very different from surface waves in many ways, the most notable of which is that a tsunami at sea is only a few feet tall at most. Even when it approaches land it behaves like a violently oncoming tide, not a cresting wave.
Factual error: Clarice, the social worker from Child Protective Services, stands around bickering with Theresa through many scenes on 12/10/03 and 12/11/03. In actuality, when a case worker is sent to remove a child from a home, he or she takes the child as quickly as possible and removes him or her from the premises at the first opportunity. This is done to avoid precisely the type of scene that occurred when Theresa arued her case with increasing desperation while Clarice just stood there with Little Ethan.
Factual error: During the 9/29/04 and 9/30/04 episodes, Fox and Whitney decide to go to dinner. Fox calls a restaurant and says they will be there in 30 minutes. When they show up at the restaurant, Whitney has changed clothes and her curly hair is now completely straight and has completely re-done her make-up. If Whitney had gone and done all of that, she would not have arrived at the restaurant in 30 minutes.