Well, I have never been pregnant so I can't tell you about the complexities of carrying a child for 9 months or even of raising one, but as for babies being parasites...well,
a parasite according to Webster's Dictionary is: "1.one who lives at others' expense without making any useful return, 2. a plant or animal that lives on or within another."...as for the 1st definition, I don't believe this to be the case for an infant human being simply because if given the chance to grow-up, he/she could make some
very "useful" returns...not only for his/her loved ones, but for society and the world in genearal. So, you could argue that a baby doesn't contribute anything...is needy..etc. But that baby has the potential to grow up and make a difference in some way. I could say the same thing about a seed. I could argue that it's got no value and isn't contributing anything, OR, I can realize that if I plant it in the ground and let it grow that I'll have me some fresh veggies someday.... And as for the 2nd definition: Yes, a baby for a certain period of time lives within the mother.The baby however, certainly doesn't stay there. And all forms of life take their sustenance from something else initially *at least that I know of*, but a true parasite spends its entire lifespan this way...babies do not.
Most importantly, babies=human=created in God's image. To call a baby/human being a parasite, IMHO, devaluates a person and shows a lack of respect for the sanctity of human life. If someone believes all a baby is is a parasite, then there is no problem with ending that babies life...and if babies are parasites, then what are we? We were all babies once...what are we now? Still parasites?
Anyway that's my opinion to the whole thing. I'm not gifted in debating or anything and I'm sure other ppl on here could give you a more intellectually sound and profound response, but I felt the urge to answer