There are many names used for both boys and girls. It makes for some confusion. Names such as: Jordan, Riley, Robin. This year alone there were 65 names that are considered dual gender names. Names that some parents would only call a girl (like Angel) are also used for boys. Likewise names that some parents would only call a boy (like Emerson) are also used for girls. So your friend should be fine with the name Riley. This year there were 8,429 babies born that were named Riley, 3,427 of them were boys and 5,002 of them girls.

Riley is a name used more for boys, but is also a girl's name. It's not widely used but is definitely recognized as a girl's name as well as a boy's. It's Irish Gaelic and it means 'courageous'. I see no reason a girl can't be courageous.

Unusual, but she should not be deterred. The name is most common as a surname.