The post-BBN evolution of 3He is considerably more complex and model dependent than that of D. Interstellar 3He incorporated into stars is burned to 4He (and beyond) in the hotter interiors, but preserved in the cooler, outer layers. Furthermore, while hydrogen burning in cooler, low-mass stars is a net producer of 3He (Iben 1967; Rood 1972; Dearborn, Schramm, & Steigman 1986; Vassiliadis & Wood 1993; Dearborn, Steigman, & Tosi 1996) it is unclear how much of this newly synthesized 3He is returned to the interstellar medium and how much of it is consumed in post-main sequence evolution (e.g., Sackmann & Boothroyd 1999a, b). Indeed, it is clear that when the data (Geiss & Gloeckler 1998; Rood et al. 1998; Bania, Rood, & Balser 2002) are compared to a large variety of chemical evolution models (Rood, Steigman, & Tinsley 1976; Dearborn et al. 1996; Galli et al. 1997; Palla et al. 2000; Chiappini, Renda, & Matteucci 2002), agreement is only possible for a very delicate balance between net production and net destruction of 3He. For a recent review of the current status of 3He evolution, see Romano et al. (2003). Given this state of affairs it is not possible to utilize 3He as a baryometer, but it may perhaps be used to provide a consistency check. To this end, the abundance inferred by Bania et al. (2002) from an HII region in the outer Galaxy, where post-BBN evolution might have been minimal, is adopted here: y3 105(3He/H) = 1.1 ± 0.2.