  Using stellar binary population synthesis code we calculate the production
rates and lifetimes of several types of possible GRB progenitors. We consider
mergers of double neutron stars, black hole neutron stars, black hole white
dwarfs and helium star mergers. We calibrate the results with the measured star
formation rate history. We discuss the viability of each GRB model, and
alternatively assuming that all bursts are connected with one model we
constrain the required collimation of GRBs. We also show the importance of
widely used evolutionary parameters on the merger rates of calculated binary
populations.
