Do executives' children have a head start over manual employees' children in terms of standard of living? This question calls for an analysis of the income distributions available to households by the family head's socio-economic group. These income distributions are like lotteries whose yield and risk are estimated based on five Family Budget survey waves from 1979 to 2000. We compare these lotteries to evaluate the extent of inequality of opportunities. The persistence of the inequality of income opportunities observed over the last two decades is due largely to deviations in expected income. The risk deviations inherent in each lottery are small. In 2000, an executive's child could hope to benefit from a 50% higher standard of living than a manual employee's child. The deviation therefore fell 20 points in twenty years. However, children of non-wage earners, especially farmers' children, have better income prospects than before. Overall, the hierarchy of income by social background has changed little, but has narrowed. The findings therefore suggest a reduction in the extent of inequality of opportunities. This change in expected income is broken down between social mobility and income growth per socio-economic group: the improvement in the prospects of self-employed and farmers' children is due mainly to higher remuneration in the professions they want to take up. Conversely, the weakening of the advantage enjoyed by executives' children reflects the fact that they find it increasingly hard to stay in their social group of origin, despite the upturn in the proportion of executives in the population. The inequality of opportunities relating to the father's socio-economic group only accounts for a fairly small fraction of total inequality. This fraction has decreased over time.