Pumpkins rotting

Can anyone help; we are growing pumpkins this year with my 8 year old, problem is as the fruit gets to about the size of a golf ball the flower end starts to rot. They are not touching the ground, they are not too wet, Any ideas?

 

My guess is poor pollenation, the weather has been against you all this summer I would say.
Perhaps now its warmed up a bit and the suns shining for a while you might get them to set.

 

Pete, thanks, i have plants which appear to have just flowers and plants which have a flower and fruit on the end. Are these males and female plants?

 

They do not grow male and female plants, you get both types of flower on the same plant.
Often a plant will produce male flowers first.
Last year I applied my usual approach (to plants of this family) I pinched out the growing points of the stems only producing male flowers, the sub lateral shoots that form usually go on to produce female flowers as well.

 

try this
http://pollinator.com/squash.htm

 

or this
http://home.rochester.rr.com/srinz/pkinpoll.html

 

Gerkin, thanks very helpful.