Conception in vitro is the result of the technical action which presides over fertilization. Such fertilization is neither in fact achieved nor positively willed as the expression and fruit of a specific act of the conjugal union. In homologous IVF and ET, therefore, even if it is considered in the context of 'de facto' existing sexual relations, the generation of the human person is objectively deprived of its proper perfection: namely, that of being the result and fruit of a conjugal act in which the spouses can become "cooperators with God for giving life to a new person". (POPE JOHN PAUL II, Apostolic Exhortation Familiaris Consortio. 14: AAS 74 (1982) 96.)
IVF, as predicted, is another slippery slope, from two parents to three and now to multiple. The intent of this technology has rapidly shifted from addressing infertility to ensuring a "healthy" baby. It is only a matter of time before these procedures will be mandated by universal government healthcare as the only option for reproduction in order to contain healthcare costs. Don't believe it? Mark my words. Catholic ping!
How about the 7 part fertilization? or a fertilization law that requires every possible racial/ethnic combination possible is put into each egg; thus outlawing normal human coitus? (sarcasm today, political reality next year)