#Freebase is a rich resource. It boasts to have 39,296,842 topics and much of it is linked to #Wikipedia. Freebase has been around for a considerable amount of time and, there are great applications that make use of the data.
One of these applications informs you if a name is typically male or female. I would not expect the name Roxy to be used by men but it is.
The information for many of the people involved is linked to Wikipedia. Consequently it is relatively easy about the sex of someone like Roxy Walters and update Wikidata. At this time no statements have been made for Roxy Walters.
The only potential problem is that Freebase is using the CC-by-sa license and that makes it incompatible with Wikidata. Given that you cannot license facts, Google may decide either to change the license for Freebase or ignore when Freebase is used to update Wikidata.