Reference for Bava Batra 252:14
רב נחמן בר יצחק אמר אף אינו נידון כבן סורר ומורה דאמר קרא (דברים כא, יח) כי יהיה לאיש בן סורר ומורה עד שיהא בן משעת הויה
he used to say to them: Go to my son Shikhath, Who is firstborn and his spittle heals'. — Might he not have been the firstborn of his mother [only]? — There is a tradition that the spittle of the firstborn of a father is healing, but that of the firstborn of a mother is not healing. R. Ammi said: A <i>tumtum</i><span class="x" onmousemove="('comment',' [H] one whose sexual organs are undeveloped or concealed. ');"><sup>39</sup></span> [firstborn] who, having been operated upon<span class="x" onmousemove="('comment',' Lit., 'who was torn'. ');"><sup>40</sup></span> was found to be a male, does not receive a double portion [as heir], for Scripture says. <i>And if the firstborn son be hers that was hated</i>,<span class="x" onmousemove="('comment',' Deut. XXI, 15. ');"><sup>41</sup></span> [which implies that he cannot be regarded as firstborn] unless<span class="x" onmousemove="('comment',' Lit., 'until'. ');"><sup>42</sup></span> he was a <i>son</i> at the <i>beginning<span class="x" onmousemove="('comment',' Lit., 'from the moment'. ');"><sup>43</sup></span></i> of [his] being.<span class="x" onmousemove="('comment',' [H] being', 'existence', comes from the same root as [H] 'and if … be', in the text cited. ');"><sup>44</sup></span> R. Nahman b. Isaac said: Neither is he tried as a 'stubborn and rebellious son';<span class="x" onmousemove="('comment',' V. Deut. XXI, 28-21. ');"><sup>45</sup></span> for Scripture says,<i> If a man have a stubborn and rebellious son</i>,<span class="x" onmousemove="('comment',' Ibid. v. 28. ');"><sup>46</sup></span> [which implies that] he must have been<span class="x" onmousemove="('comment',' Lit., 'until he shall be'. ');"><sup>47</sup></span> a <i>son</i> at the<i> beginning<span class="x" onmousemove="('comment',' V. supra n. 3. ');"><sup>48</sup></span></i> of[his] being.<span class="x" onmousemove="('comment',' Cf. I.e. n. 4. The Heb. for have in the text cited, is [H] of the same root as [H] ');"><sup>49</sup></span>