My kids are Trekkies, and it's wonderful. K got a phaser for Christmas, which he loves. Actually, both kids love playing with it. Their path to being Trekkies began before birth, really. When I was pregnant with K, towards the end of the pregnancy, I'd watch Star Trek: Voyager every evening. Once he was born, we continued that, and it was generally comforting for him. He even started asking for Voyager at night, though we stopped watching every night. If he's having trouble getting to sleep, though, we do sometimes put it on for him. Just a couple of days ago he greeted us in the morning by saying "I need Star Trek". It didn't work, but it was cute. I think I need to knit him a Starfleet-inspired sweater sometime.
C also enjoys Star Trek, both TOS and Voyager. If we watch Voyager with her, she'll stop whatever she's doing when the theme song comes on to watch that part, just like K used to do.