According to the standard model, millisecond pulsars are the descendants of low-mass X-ray binaries (LMXB). The importance of this formation route has, however, been questioned by several authors on different grounds. This paper critically reviews the arguments and assumptions underlying the standard model. The kinematic properties of the LMXB and millisecond pulsar populations are compared, and are found to be compatible. This provides an additional argument in favour of the standard model.