I don't think it's wrong to lie to children, if there's a good reason for the lie. I recall my daughter hearing the word "rape" and asking what it is at a very early age. I said I didn't know with a "that's not important" tone of voice. Sure, I could have made an honest statement about her being too young for the subject, but it seemed pointless to make her feel disrespected, or to let her go on wondering about the matter.
But does it make sense to lie about where babies come from? I frankly don't understand why parents feel so giggly and embarrassed about the subject. I told my twins the facts of life gradually, probably starting around the age of 3 or 4. When they asked how sperm gets into the mother's uterus, at about age 5, I told them the truth. (They thought it was the funniest thing they'd ever heard.)
If a parent lies about where babies come from, are they immoral? Some lies can cause children anxiety, and then there's reason to disapprove. For example, a friend of mine was asked by her 4-year-old how babies come out of their mothers. My friend couldn't bring herself to discuss the basics of female anatomy. So she said mothers push, without explaining the route of egress, or what pushing might mean in this context. I imagine the child may have found this image disturbing. Without knowing about the...er, vagina...the child would have had strange images in her head. Maybe the baby crashes through the mother's side when she's done with all that pushing?
The "make a wish" lie you mention sounds sweet and innocent, but I'd worry about misunderstandings. "If Mommy and Daddy love each other very much, can they close their eyes and wish for just anything? And if so, why don't they get me everything that I want? Maybe they don't love me!"
I think there are necessary lies, but lying about where babies come from isn't necessary, and can be harmful.