That's not entirely true... I'm not saying it's even CLOSE to as easy or as cheap as collecting sperm, but woman are able to have their eggs collected and frozen for future use.
Spanking one (or many) out in a cup at a collection center has virtually no risk to the man.
Check into Ovarian Hyperstimulation Syndrome...
http://www.advancedfertility.com/ovarian-hyperstimulation.ht...
I'm not aware of mainstream (or any, really) permanent solutions for women, at least not to replace contraceptives (medical reasons - like cancer - for an invasive surgery don't count).
So, if women usually don't decide to become sterile (?), the process to collect and store eggs seems less relevant.