Most drug design methods produce a large number of leads that can be subsequently filtered based on the calculated value of LogBB. However, it is not efficient to do so, as most molecules will fail to pass the filter. This is illustrated in this work by a comparison of the populations of molecules generated with Autogrow4 and STgrow4. STgrow4 can direct the evolution of the population for the design of molecules with desired properties, such as high LogBB. The results of this work demonstrate that incorporation of the required information regarding LogBB during the evolution process is more efficient than the use of filters for LogBB after evolution based on binding affinity.