Personally, I find it easier to have a female voice in English (BUT only if I'm alone ; I get too embarrassed when talking to someone), mainly because as it's not my mother language, I tend to use my "official" tone [ya know, the one you use when you hear "May I talk to Mrs. X, please?" while waiting for a job call], which is naturally higher. It's also the only tone I can sound truly female with.
In any case, languages are different, I guess. I know nothing about Dutch, but if it looks like German, it does look harder to sound female in it. From an outside point of you, German sounds, you know, brutal. It's a common joke here to say that hearing "Ich liebe dich" sounds more like "I want to devour you" than "I love you".