database INSERT and UPDATE converts symbols to html code

I have a registration form. If I enter a word such as can't, the INSERT and UPDATE functions replace the ' with  in the database.

It will display fine, but if I populate the form with database entries in order to edit the information, the field shows
can't with the html code for ' instead of the ' .

If I then re-submit the form after editing, the html code for '  is replaced by & and the html code for '  in the database, and so on. 


This is really bad for the user. Besides I don't want the html code
for ' to be stored in the database, I want the actual word can't. What can I do to prevent this?