John Dominic Crossan
Crossan sees 24 Blessed the Womb as a twin to 105 Jesus True Family, and considers them together when discussing Jesus' attitude towards traditional (patriarchal) family life [Historical Jesus], (299). In both cases the tradition is shaped as a dialogue rather than a simple aphorism. Other clusters that relate to Jesus' attitude towards the biological family are 074 Peace or Sword, 089 Hating Ones Family, and 015 Against Divorce.
Despite the notation (Five Gospels),  asserting that Thom 42, Become Passers By, was the only saying on which the Fellows split 50/50, the vote on Luke 8:21 had 60% voting Red or Pink and yet a weighted average of 0.50. This is a reminder of the limitations inherent in the Seminar's statistical processes.
The commentary on Luke 11:27-28 in [The Five Gospels] (p. 331) observes:
The Fellows of the Seminar were divided on the authenticity of the various versions of the saying on hearing and doing. Some versions commanded a pink weighted average (Matt 12:50; Thom 99:2), others fell into the gray area (Luke 8:21; Luke 11:28; Thom 9:2), and still others were designated black (Luke 6:47; Matt 7:21). The vote in all these instances undoubtedly reflects some judgment about the context in which the particular version occurs, as well as judgments about specific words. The Fellows were of the opinion, for example, that in this context Jesus would have been more likely to use the phrase "my Father" than to employ the term "God." The saying in Thom 79:1-2 and Luke 11:27-28 received a gray vote, because many of the Fellows doubted that the narrative setting recalls an actual situation in the life of Jesus.
Verse 27b was not spoken in the lifetime of Jesus, but probably later, to glorify his mother. In any case the present scene has no claim to historicity. [Jesus], (339)
Meier refers to this cluster, including the Johannine and Jacobean versions, when considering the wider question of Jesus' beatitudes in the Q tradition [Marginal Jew] (II,325-333). He notes that Q, M, L, John, James and 1Peter all provide evidence for Jesus having spoken beatitudes, but that the historicity of any particular saying must be judged on its own merits as they represent a popular form of expression long before and long after the time of Jesus.
In Marginal Jew III,70 (see also n. 102 on page 113), Meier notes the brusque and negative tone that this saying must have had "when it circulated as a stray nugget in the oral tradition" prior to Luke's softening redaction.