Michelle Williams has spoken out in defence of former Destiny's Child bandmate Beyonce Knowles' decision not to tame her daughter Blue Ivy's wild hair. The singer says critics should focus on their own kids.Style critics and internet trolls have taken aim at the Crazy In Love hitmaker and her rapper husband Jay Z in recent months over their choice to let two-year-old Blue Ivy's locks grow out naturally.The haircare debate even led to an online petition, calling on the baby's superstar parents to comb her locks, but Williams is baffled by the unlikely hot topic, reports contactmusic.com."Let's worry about your own children and nieces and nephews and make sure they're getting good grades in school and not worry about somebody's hair,” she told America's Sister 2 Sister magazine.Williams has also warned cyber bullies everywhere not to mess with her or her loved ones."I think the cyber bullying is just stupid because the majority of the time most of the cyber bullies just type it (online), but when they see you on the street, they're not gonna say it to your face,” she said."Every now and then, depending on what day you catch me, if you say something out of line to me -- because I don't want you to be ignorant, I want you to be knowledgeable -- I will spit something back to you that's factual and I'll say 'God bless you' at the end,” she added.