In "Fortunate Son" Mayweather said about how he had a sister and brother-in-law back on the Horizon. But then when he returned to the freighter after his father's death, there was so sign or mention of a sister, but instead he had a brother who he was rivals with. Did she have a sex change and become his brother? Or is there a rule that brothers and sisters can't have rivalry between them? If a line had been used that his sister had moved away to another ship, or a planet somewhere, I could live with it. But there is nothing like that. Its the little things like that which really annoyed me about ENT.
It's the Chuck Cunningham Syndrome. http://tvtropes.org/pmwiki/pmwiki.php/Main/ChuckCunninghamSyndrome
And then there's Sisko father who was mentioned as having died and then he shows up alive and well in later seasons of DS9. I think these things are the result of all the time travel in Trek or is it Superboy punching the walls of reality?
I've not actually seen it that often, but that was just one of the things that stuck out to me. Hmm, I can't remember that at all. Sisko used some past tense when talking about him on occassion, but I can't remember him actually stating his old man as having died. There's only one thing for it...I must rewatch DS9 from the beginning
Sisko's dad was never explicitly stated to be dead, though on the few occasions Sisko did talk about him before Season Four, the tone of Avery Brooks' delivery certainly made it seem like he was dead. So they were able to skirt around that one thanks to a technicality, but it still kind of threw me off for a while when Joseph Sisko first appeared.
That traitor that looked like Johnny bravo at the end of Enterprise used to be a girl. I'm not sure how he shot himself in the head through all that hair-gel.
Actually Travis' mom says that she'd received letters from Travis' sister and that is how she knew all of the more exciting stuff Travis had done and not just the safe stuff he reported to his mother. Clearly the sister is living somewhere else.