Given that the Europeans wanted a laboring population to work in their most advanced industries and were willing to pay well for these workers, it was evident that the aged and the infirm were not selected.
Not only would they not have survived the transportation experience, but they would have proved useless for the major manual laboring tasks demanded by the American planters and slave owners.
Thus, only the healthiest persons were sent into the Atlantic slave trade. These tended to be mostly males – just under two-thirds of the total migration stream whose age and sex is known – and three-quarters were adults.
But these overall age and sex ratios tended to mask sharp changes over time, with both the ratio of males and of children rising through the centuries.