There are pros and cons to both..........but the bigger question is whether you should have a pair or not.
Guinea pigs are social animals and while single pigs will sometimes work, they are best kept in pairs. In fact, in some countries keeping one guinea pig is illegal as it is considered animal cruelty.
Both male and female pigs have pros and cons. Males tend to smell more, females spray their pee. There is quite a list. Females tend to get along better, especially in larger herds. But not always.
Boars are sometimes difficult to pair. While I've never had a bonding go bad, I have had pigs that are the sweetest, best buddies you could ask for and I've also had pigs that simply tolerated each other. Each one has its own unique personality, just like people.
I also applaud your research before getting an animal. BUT, also ask yourself if you can afford their veterinary care. More often than not with these creatures its not a question of IF they will need care, but WHEN. They require a specialized, exotic vet for appropriate care, and I would see if your parents would be willing to help if that eventuality arises.
