There are a number of reasons that would go to book-length (no, I won't do that here!) but let me just speed through the biggest ones summary-style.
The most obvious problem is that IVF "begets" or produces more offspring than will be implanted in your womb. That results in two really inhuman options: (1) killing your "surplus" offspring (or storing them in frozen form until they deteriorate and are ultimately dumped); or (2) using the embryo as a human experimental subject, without any of the safeguards essential to its moral status as a nascent human being.
The third problem is that the entire process of ovum extraction, sperm collection, in vitro fertilization, and so forth, has already reduced human procreation to an laboratory procedure resulting in a product who/which is a commodity in commercial transaction.
The entire distinction between a human being, a lab animal, and a bit of biological property is in smithereens.
So we (Americans) are right back where we were at the time of the Dred Scott decision of 1857, with the law unable to distinguish between a human being and a piece of property. Except at a potentially worse degree of complexity, since the human genome can now be altered through the introduction of heterologous genes, and the embryo manipulated into forms of abnormal development, so that distinguishing between "human" and "not-human" becomes almost impossible.
When Aldous Huxley wrote "Brave New World," he assumed --- didn't he? --- that people would want to prevent this from happening. There must be somebody out there who is thinking strategically about how to stop this whole race to total depersonalization. I think it should be done.