The breakthrough, which came by unlocking the intricacies of male reproduction, could also lead to new contraceptives and a 'miracle pill' to treat infertility, they say.
For the study, the American scientists used a cocktail of chemicals to wind back the 'biological clock' in skin cells, turning them into cells with the chameleon-like powers of embryonic stem-cells, the 'Daily Mail' reported.
They then used a combination of nutrients to coax them to develope into round cells which were just a few steps away from mature sperms and appeared genetically normal.
The University of Pittsburgh School of Medicine team, led by Dr James Easley, believe they have cracked the most difficult part of sperm development.
This means that by altering the procedure it should now be relatively easy to get to the next stage - elongated cells that, while yet to grow tails, should be able to fertilise eggs.
The technique is still many years away from use in clinics, however, the science is fraught with moral and ethical concerns.
Critics argue that it is wrong to meddle with the building blocks of life and warn of a future in which babies are created through entirely artificial means.
Scientists have already succeeded in coaxing embryonic stem cells, which are master cells plucked from embryos in their first days of life, turning them into sperms.
Using skin as a starting point would be more ethically acceptable as it would also mean the sperm would have the man's genes.
The study was published in the journal 'Cell'.
