**** (4 stars out of 5)
Klingon pregnancies are typically 30 weeks, but with mixed species it can be much quicker. (Which, as you'll recall, could be a good explanation for Alexander Rozhenko.)
B'Elanna and her mother each had corrective surgery in infancy for hereditary spinal curvature, but the EMH can now genetically modify the fetal spine and save the hassle. Unfortunately, Torres starts brooding about other possibilities for gene modification...
Klingon traits remain dominant for several generations, so Baby Paris-Torres will have forehead ridges. Mommy proposes something the Doctor finds very dubious: she wants to delete gene sequences for redundant organs like her third lung and such... but mostly she wants to have a little blonde human rather than an ugly, ugly Klingon.
B'Elanna grew up feeling the sting of human discrimination even from her own relatives. And despite the Bolians, Vulcans, Talaxians, and Bajorans aboard, there are still 140 humans. And the cream is white! In fact, once the Doctor has a sudden, conveniently engineered change of heart, Baby Torres may turn out white, too.
"Lineage" offers a lot of insight into B'Elanna's heart. The pain of her parent's divorce, her difficult path as a daughter of two races. Humans may have put their racial differences behind them in this future (to the point where the meanest name kids called B'Elanna's father was "John SNORE-es". But merging cultures is not and never will be easy. It takes a village and this kid would have a doozy: Bolians who think being born near a warp core is good for the disposition. A space-faring Indian for a spiritual advisor. And a hologram for a godfather.