Schwa in Hebrew is masculine, but in German (and Latin) it's neuter. There are two famous sounds in IE philology: schwa indogermanicum (primum) and schwa (indogermanicum) secundum. Today they're not even considered schwas, except by hardliner anti-laryngealists, having been replaced with a series of circa three laryngeals (deep throat sounds like ’ayin in Hebrew or Arabic, or pharyngeal fricatives like the sound represented by IPA gamma). I'm not quite sure why the IEists, like Hirt, wrote das Schwa indogermanicum mixing German and Latin, but they did. The laryngeal theory is a long and complicated one which I'll save for another entry.