In the process of examining what then-Cardinal Ratzinger (now the Pope) might think about evolution, John Allen provides the following quote from Ratzinger, which can be found included in Ratzinger's book Truth and Tolerance:

No one will be able to cast serious doubt upon the scientific evidence for micro-evolutionary processes. R. Junker and S. Scherer, in their 'critical reader' on evolution, have this to say: 'Many examples of such developmental steps [micro-evolutionary processes] are known to us from natural processes of variation and development. The research done on them by evolutionary biologists produced significant knowledge of the adaptive capacity of living systems, which seems marvelous.' They tell us, accordingly, that one would therefore be quite justified in describing the research of early development as the reigning monarch among biological disciplines. … Within the teaching about evolution itself, the problem emerges at the point of transition from micro- to macro-evolution, on which point Szathmáry and Maynard Smith, both convinced supporters of an all-embracing theory of evolution, nonetheless declare that: 'There is no theoretical basis for believing that evolutionary lines become more complex with time; and there is also no empirical evidence that this happens.

Now the book by Junker and Scherer is a controversial German anti-evolution text; and the provided quote from the book by Szathmáry and Maynard Smith is one that has been horribly ripped out of its context, having nothing at all to do with any distinction between "micro-evolution" and "macro-evolution", and this has led one of its authors to complain that its use by Ratzinger was "misleading and inappropriate" (though it is probable that Ratzinger relied wholly — but wrongly — on Junker and Scherer for the appropriateness of the quote).

It is thus not unreasonable to suppose that Cardinal Ratzinger devoted little time to reading in science, and thus largely missed the scientific significances, contexts, errors and controversies of Junker and Scherer — in a way that he would be most unlikely to do for any philosophy or theology book.

Is that worrying?

On one hand, it's not worrying. Understanding science is not high on the list of expected duties of the vast majority of ordained priests, and so in general not much is provided to them.

On the other hand, more and more problems necessitate scientific understanding (evolution, cosmology, stem cells — and worse headaches to come) in order to locate them meaningfully within the realm of faith and morals. The difficulty (and it is an extremely widespread difficulty indeed) is that lacking a needed scientific understanding, people will often try to use only philosophy and theology in order to discuss these subjects — and that will often simply fail to provide useful answers. A bad scientific idea can be supported by appeals to good philosophy and theology. Then, lacking a good scientific understanding, some people may erroneously come to regard the bad science as good. (As has been seen in discussions of intelligent design, oh …. about a million times.)

(From other things, I know Ratzinger had a good idea of when he was starting to step inside the scientific field, and thus backed away a space.)