I succesfully added first and last name input fields to the registration form. They are input fields type text.
When trying to add a field 'description' for Biographical Info as textarea it is present on the registration page, but user input is not shown at the registrars profile. It works only when the input fild is type text.
To implement i used these instructions http://www.jfarthing.com/development/theme-my-login/adding-extra-registration-fields/