1. Grocery stores mainly sell unfertilized chicken eggs although fertilized eggs can be purchased from specialty markets. So most omlettes consist of chicken ova. Even so...
2. There is a pretty big difference between a chicken and a human child.
"Is a fetus a human being? This seems to be the central question. Well, if a fetus is a human being, how come the census doesn't count them?"
The census doesn't count them because Roe v. Wade is law and people like George Carlin would be outraged.
"If a fetus is a human being, how come when there's a miscarriage, they don't have a funeral?"
Some cultures/religions do. But Carlin's question is a diversion. It's a cultural/religious question, not a moral question. If I died and no one gave me a funeral, would that invalidate my humanity? And if I buried my goldfish in an expensive casket, invited guests, sang songs and wept loudly would that make him human?
"If a fetus is a human being, how come people say 'we have two children and one on the way,' instead of saying 'we have three children.'"
1. Many people do count the in-womb child, but Carlin is once again refering to a cultural phenomenon.
2. In China they calculate age from the estimated conception day. The birthday is just the birthday; it marks the day of birth. It is not "lifeday". So in China, a place where forced abortion and infanticide are rampant, the child is already acknowledged as a living human being on the day of conception.
3. I've said that I was green with envy before, but that is not evidence that I've literally changed colors. People say a lot of things.
"But even after the egg is fertilized, it's still six or seven days before it reaches the uterus and pregnancy begins."
1. Actually, physicians, many of whom support and even perform abortion, count the two weeks prior to conception as the time when the pregnancy has officially begun, so Carlin doesn't have the patent on when pregnancy begins. Doctors count the two non-pregnant weeks of pregnancy to more precisely pinpoint an estimated date of delivery as many women do not know when they conceived but do know when their last menstrual cycle began. If a woman is 40 weeks pregnant her child's gestational age is 38 weeks. What this shows is that Carlin doesn't understand basic concepts related to pregnancy and has very little authority on the subject.
2. A person can implant in his mother's fallopian tube. This is referred to as an "ectopic pregnancy" even though the child has not made it into his mother's womb. Once again, a simple concept.
3. When an egg is fertilized it immediately posesses 23 pairs of chromosomes (or, in the case of an anomaly, a different but equally valuable number, as different ability doesn't make a person inhuman). Eggs and sperm only have one set of chromosomes and no pairs. A human being has pairs. A blastocyst does not resemble a fetus, a fetus doesn't entirely resemble a toddler, and a toddler doesn't entirely resemble a teen. A teen doesn't entirely resemble an adult and I don't resemble a senior citizen... entirely... although I'm well on my way. However, all the while I've had and will have 23 pairs of chromosomes. So, unless a person is an advocate of discrimination based on physical appearance, I think it matters little what I look like; I'm always human. I was a living human being, me, the moment my cells possessed their own set of chromosome pairs and began to divide. It doesn't matter how big I was, what I was capable of doing or thinking, what I looked like or where I lived. This is basic science. When human life begins, pregnancy begins.