Electroweak precision data and the fourth family

The easiest extension of the Standard Model is a sequential generation of (heavy) fermions. Referring to the electroweak oblique parameters, the particle data group excludes a mass degenerated fourth fermion generation at the 6 σ level. We want to show that these arguments against the existence of a fourth family can be relaxed if we take into account quark mixing. This is the result of fits in the parameter space of the standard model with four families, which were generated using the CKMfitter software. Moreover, we will discuss the correlation of the fourth family and the Higgs mass.