I could not remember the security question asked about the nickname of my oldest son. What should I do now?
Please use Yahoo Live Support because they will provide the security questions for you. The only way to recover a password of your Yahoo account is the help of a Support Assistant. They assume that you have forgotten the password and provide the security questions so that you can answer.
If you can't then you should actually enter you phone number and Yahoo! will send a code to your mobile, just type that code in the given box and you shall be able to open your account. Hope that it works. :) ^.^