Hello, http://www.fileformat.info/ seems to provide valuable data on fonts. Gentium font is listed amongst fonts providing the Thin Space char : http://www.fileformat.info/info/unicode/char/2009/fontsupport.htm This other page confirms it : http://www.fileformat.info/info/unicode/font/gentium/blockview.htm?block=general_punctuation and also the page on the foundry site : http://scripts.sil.org/cms/scripts/page.php?item_id=Gentium_Technical#KI states it includes the interval U+2000..U+2030 that includes +2009 (thin space) and other spaces.
However scribus doesnt provide the ability to insert that thin space and any other space apart normal and non breaking space... I've tryed with various gentium alternate sets : plus, basic, alt, etc I'm not an expert on fonts so am i doing something wrong ? or maybe scribus ? or how to access these spaces through scribus ? Beside a nice 1.5 scribus soon, I wish you all a wonderfull 2013 year ! JLuc