This study followed a group of 252 students in Stockholm from 7th grade to the first year of Gymnasium (High School). This ongoing four-year study began in 2000 and is the only full-scale experiment of its kind in the Swedish school system. It was initiated and followed by policy- makers in Stockholm as well as on the national level. Three sub-studies have been completed, and the concluding report will be finished in April 2005. In the final report we will analyse the correspondence of family background to our earlier results, grade scores in 9th grade and analyse the choice of Gymnasium program for students in the M/S classes/Schools.The goal of these classes was to encourage students with Math and Natural Science aptitudes towards continued studies at Gymnasium. Additionally, the classes aim to give gifted students the chance to earn High School credits in Junior High so that they are able to begin studying college courses while in High School.The third sub report, examined the students' (totalling 1805) transition to the Natural Science programs from the 8 M/S schools and the 8 control schools. We also looked at students' grade point averages in Natural Science in 9th grade spring semester 2003 and compared grades between 8th and 9th grade students. Additionally, we studied how many of the nearly 6000 9th grade students in Stockholm gymnasiums had taken A-courses in Math in 2003.We found that students who attended M/S classes transitioned more easily to the Natural Science program than other students. They also had a higher total grade point average, a higher grade point average in Math and a smaller grade spread in Math. The difference in grades between girls and boys was also less in theses classes than in other classes. Nearly half of the students in the M/S classes, 43 percent, began the Natural Science program. Compare that to 22 percent in the control classes, 16 percent in the other classes at the control schools and 12 percent in the other classes at the M/S schools. There was, however, a rather large difference both between the eight M/S schools and the ten M/S classes in the amount of students who began the Natural Science program.There was no apparent connection between the composition of the population in the school district and the amount of students who started the Natural Science program. Likewise there did not seem to be any connection between a high grade average in Math in a M/S class and the transition to a Natural Science program at Gymnasium.To support interested students, the M/S project offered a possibility to attend a Mathematics course at Gymnasium. There were only a few students, 98, from the 9th grade that took the A-course in Math, fall semester 2002/ spring semester 2003. Most of these students attended a M/S class. Not only students from the M/S classes, but also students from other classes at the M/S schools took the A-course in Mathematics. This implies that the investment in M/S classes has also benefited other students at some of these schools. More than 71 percent of the 98 students came from M/S schools, 2 students from the control schools and 26 students, more than 27 percent, came from other schools in Stockholm.