Complex sentence: He is often cited by creationists as an example of a scientist who rejects evolution, although like many such people, his background is not in biology and the principal motivation for this rejection is apparently out of theological, rather than scientific reasons.
Split into simpler sentences: He is often cited by creationists as an example of a scientist who rejects evolution. However, his background is not in biology and the principal motivation for this rejection is apparently out of theological, rather than scientific reasons.