Perhaps they want to de-emphasize the military aspect of the show in the opening credits and make the crew more "a family" in the eyes of the viewer?
Producer #1: "'Family'? I like it! How will we do that?"
Producer #2: "Well, sir, I was thinking in order to make it more
family, we'd introduce a new character."
Producer #1: "A new character? Excellent! And what will this new character be like?"
Producer #2: "Well, she'll be a female."
Producer #1: "Ah, like a grandmother? A family-friendly grandmother."
Producer #2: "No, she'll be a sex symbol who parades around in a skin-tight cat suit."
Producer #1: "A
family friendly cat suit?"
Producer #2: "No, a sexual object cat suit."
Producer #1: "Excellent! And how else will we make this more
family in nature?"
Producer #2: "Well, I was thinking we could then make her trhe sexual object of one of the male characters onboard who never get any."
Producer #1: "I like it, has 'family' written all over it! What else?"
Producer #2: "Then later on we will make her the sexual object of a hologram."
Producer #1: "Doesn't make sense, but I like it! It earns me a secure paycheck! Then what?"
Producer #2: "Well, then in order to continue this family environment, we'd have her create angst and bickering amongst the leads who should be setting a better example."
Producer #1: "Sexual angst???"
Producer #2: "No, just regular angst."
Producer #1: "Oh well. I like it anyway! Then what."
Producer #2: "Well, in order to make this 'family' more cohesive, I thought we'd take the equivilent of one of the captain's brothers, mutate him, have him have sex with her, then her give birth to his incestual lizard babies."
Producer #1: "Sounds hot! then what?"
Producer #2: "Then later on I'd have the equivilents of a brother and sister in this 'family' continue a relationship, have sex, and give birth to a kid out of wedlock in inter-species relations which we previously made a no-no for Harry Kim. 'cause he's not allowed to get any."
Producer #1: "Oh, I'm getting all horny over this family idea!"
Producer #2: "Speaking of 'horny', the captain, i.e. the mom, will have a romance with her dad. The dad that later tries to get it on, as I said, with tyhe equivilent of his cousin."
Producer #1: "OH! I'm gonna need a towel."
Producer #2: "Sigh. I'll go get the towel Mr. Berm -- I mean, Producer #1."