Distribution of orbital periods for all observed recycled pulsars (MSPs) with He WD companions in the Galactic field. In total there are 35 systems with P_orb< 10 days; four of these are the solutions (P_orb< 9h) marked with orange. Data from the ATNF Pulsar Catalogue Manchester et al. (2005) – version 1.50, July 2014. The red dashed line shows the distribution of systems that would be expected from our calculations using standard input physics (i.e. using the results presented in Fig. 6), thus illustrating the orbital period fine-tuning problem.