Probability of forming planets as a function of metallicity and stellar type. Upper panel: probabilities of forming gas giant planets as a function of [Fe/H] for M, FGK and retired A proposed by Ghezzi et al. (2018) are shown with the black, blue and red lines, respectively. The probabilities have been IMF weighted according to the procedure described in Section 3.1. Fischer & Valenti (2005) relation is also shown with the dashed grey line. Lower panel: probability, P_E, of forming Earth-like planets and not gas giants (GG BAD case) as a function of [Fe/H], and indicated in Eq. (6) for different stellar spectral types, shown as solid lines. In contrast, the dashed lines illustrate the new scenario discussed in Section 3.3 and called the GG GOOD case, which assumes that the presence of gas giants enhances the likelihood of terrestrial planet formation. All the cases are computed using the gas giant probabilities of Ghezzi et al. (2018).