Nedarim, Chapter Three, Mishnah Nine
This mishnah deals with someone who swore not to receive benefit either from those born or from those who are to be born.
One who vows [not to benefit] from those born may [benefit] from those to be born; from those to be born, he may not [benefit] from those born.
Rabbi Meir permits [him to benefit] even from those to be born;
But the Sages say: he meant all whose nature it is to be born.
We will understand this mishnah better if we take note of the Hebrew. The word those born is yilodim and those to be born is noladim. The former term does not encompass the latter, and therefore, if one swears not to receive benefit from yilodim he may still receive benefit from those who are to be born, the noladim. However, the latter term does encompass the former, and therefore, one who swears not to receive benefit from noladim cannot benefit even from those who are already born.
Rabbi Meir disagrees and holds that one who swears not to receive benefit from those who are to be born, the noladim, can receive benefit from those already born, the yilodim. To Rabbi Meir both terms are completely distinct.
The Sages disagree. One who swears not to receive benefit from the noladim does not mean that he will not benefit from those who will be born, but rather from those whose nature it is to be born. This would encompass all of humanity.