ok... devil's advocate mode on.....
If you/your son were racing and desperately trying to secure sponsorship. You had some good results, but unless you got some help were not going to be able to race next year.
You have been approaching lots of companies for help with sponsorship and you are making good progress with a particular supporter.
Suddenly the sponsor backs off and you discover that they are putting their money into a female rider who has only had some fairly average results but is fairly attractive and so gets some attention.
Would you see that as fair??
You could argue that as a sponsor they want to get the best return on their investment and a female rider is likely to get more publicity (if she tries) so would give better returns. But would the fact that she is female and using the girly angle make it fair in your eyes?
Just for refrence, i think its fine, in the sponsorship world its a fight to the death and any way of getting it is fair game as long as its honest. It may well be unfair to the better male rider, but things usually even themselves out.