The reason it's higher is because most transfers involve multiple embryos.
No, that was another person's implication. Mine was that society should be legally obligated to take care of all those that require it. As to the above, however, you're countering your own point. In the case of birth, there is a legal expectation in regard to providing for that entity. it can be transferred, but it must be upheld.
In relation to the abortion question, if you force women into carrying babies to term, you need to also address what happens after birth. To not do so. you're essentially saying that abortion is murder, but death by negligence/starvation is of no concern.