apache wordpress and zombies

I installed 2.04 WP on the server (Centos with Bluequartz) for me and my customers .. but suddenly ….

httpd is showing me a lot of zombies the last 2 or 3 days
when checking with ps -aux I see apache …….. “[host] <defunct>”
checking pstree -lp I see that httpd is creating them

httpd is |-httpd(9773)-+-host(10896)
| | |-host(10966)
| | |-host(11015)
| | |-host(11117)
| | |-host(11518)
| | |-host(11591)
| | |-host(11709)
| | |-host(11873)

etc…

top shows me:
382 zombie processes at this time.

Of course I can restart the httpd process (which is does itself every night) to solve it, but I want to see the cause and why it’s happening ..

I want to know; what are zombies, what are they doing and does it hurt?

if it’s not something okay how to get rid of it ?

It probably due to ‘WordPress Weblog’ software as I see the live – hits an checking the zombie counting with TOP
and right now the server is hit by GoogleBot ..
so with every hit a zombie proces is created ..

Can anyone else confirm/verify etc?

Thanks
Dennis