After presenting arguments that the number of highly cited papers (HCPs, 25 or more citations) has some advantages as an indicator of an author's scientific impact, the paper discusses citation data of 338 university professors in departments of medicine in the Netherlands. An analysis of the distribution of HCPs over the years provides support for the following conclusions: (1) prolific researchers with a large number of HCPs usually manifest themselves already in their Ph.D. work, apparently almost independent of the scientific setting; (2) it cannot be taken for granted that a successful Ph.D. student with some HCPs connected with his/her doctoral thesis will become a prolific successful researcher; (3) it is unlikely that an unsuccessful Ph.D. student without HCPs connected with his/her doctoral thesis will turn out to be a prolific successful researcher; and (4) for researchers, just as for artists, sportsmen, etc., talent is the most decisive factor in being successful.