More than one female said so.
I think cute is not manly. why don't you call him handsome? seriously, calling a guy handsome makes you sound alot more mature. and there's no need a proof for it. But being called cute (at least for me) makes me feel like I'm 5, and obviously it's like a furry little stuffed animal.
Why should I care if it sounds manly? Too much importance is placed upon masculinity.