I'm growing several cucumber and courgette plants in my sunny attic room. I have noticed though that:

a) little cucumbers are growing followed by flowers - do I need to do some pollinating for them to develop further ? Are the flowers male or female ???

b) I have a few courgette flowers, but nothing resembling a courgette. Do I need to break into these flowers and do some pollination for them to fruit ???? Is the sex - ie male or female predetermined ???? If so why do I need to pollinate ????

This is my 1st year of growing these so would like some success !!!!!!
Any help greatly appreciated
Lissy