What gender?

That's a nice bicycle. Merida is a good quality brand.

There are guys who ride pink bikes. There are world champion men who proudly display the rainbow jersey in big events and aren't gay. My wife loves blue and has several bikes with blue all over them.

Also, look at this recent thread. While it doesn't deal with gender, it does deal with concerns about appearance and what people might think. Take note of the comments that people are more likely to be concerned with their own world, than what others look like, and other than to say "what a neat looking colour" on that Merida, they'd probably be more interested in the disc brakes and tyres.

And finally, if the bike fits your sibling, and is comfortable and does what s/he wants, colour is the last thing on the list that should be of concern, gender issues or not.