Reference for Bava Batra 71:10
אמר רבא אם היה קטן מוטל בעריסה יש לו חזקה לאלתר פשיטא לא צריכא דאית ליה אימא מהו דתימא ניחוש דלמא אימיה עיילתיה להתם קמ"ל אימא לא מנשיא ברא
Raba further said: If the slave is an infant in a cradle, presumptive right to it is conferred immediately.<span class="x" onmousemove="('comment',' Because the child could not have got into the house by itself; hence the presumption is that it was bought from the previous owner. ');"><sup>18</sup></span> Surely this is self-evident? — It required to be stated on account of the case where the child has a mother. You might think in that case that there is a chance that the mother brought it into the house where It now is [and left it there]. [Raba therefore] tells us that a mother does not forget her child.