Well, duh. If she only had two children, she'd be getting too close to the Capitalist Ideal of the Nuclear Family.
The wartime Soviet government gave medals and pensions to particularly productive labor-unit manufacturers mothers, although Gangut is going to have to look beyond the Special Type IIIs if she wants to qualify for the Order of Maternal Glory (minimum 7 children for 3rd-class badge), much less earn her Mother Heroine medal (10 or more).
On the other hand, if she annexes the whole Fubuki class, there's what, 24 of them? (Not all of them are in the game, admittedly, at least not yet.) She'd probably even get an autographed photo of Stalin for that accomplishment.
