Hmm...I noticed there are a lot of boys who are afraid TMGC is too girly, but I am a girl who is worried that TMGC is too boyish! There are some anime episodes that are so boyish..
Anyway, you can easily tell Tamagotchi is not just for girls. If it was, the main character would be a girl and it would be all pink and flowery and all that stuff. So, Tamagotchi is equally for boys and girls. Don't worry about it! My brothers like Tamagotchi (mostly the show) and I used to see a lot of boys with Tamagotchis.