Complex sentence: The upper limits of Rothstein's growth spurts are unclear, but heights above 50 feet are believed to tax his molecular structure and could cause permanent cell damage; however, in the DC Encyclopedia, it stated that he could grow up to 60 feet without problems.
Split into simpler sentences: The upper limits of Rothstein's growth spurts are unclear, but heights above 50 feet are believed to tax his molecular structure and could cause permanent cell damage. However, in the DC Encyclopedia, it stated that he could grow up to 60 feet without problems.