Is the weak interaction constant really constant?

A comparison is made of the probability of the process of two neutrino double-beta decay for 82Se and 96Zr in direct (counter) and geochemical experiments. The experimental data for 130Te are also analyzed. It is shown that the probability is systematically lower in geochemical experiments, which characterize the probability of ββ(2ν) decay a few billions years ago. In addition geochemical measurements on young minerals give lower values of T1/2(130Te) as comparedto measurements on old minerals. It is proposed that this could be due to a change in the weak interaction constant with time. The possibilities of new precise measurements to be performed with the aid of counters and geochemical experiments are discussed. A new geochemical experiment with 100Mo is proposed.