Safety wise, a bad thing to do. The UBC and IRC are both minimum safety codes for building. Ask your local Building Department. Here are the main reasons why to have windows in a basement:
Bedroom and Basement Egress Windows
Sill height 44in. max. above finished floor . .
F-b13 [310.1] {310.4}
5.7sq.ft. min. clear opening . . . . . . . . . . . .
T-b9 [310.1.1] {310.4}
Min. 20in. width and min. 24in. height . .. .
.T-b9,
F-b13 [310.1.2,3] {310.4}
No windows <3ft. to property line . . . . . . . . . . . . .[302.2] {T-5-A}
Security bars must have approved release hardware [310.4] {2320.13}
Window wells min. 9sq.ft. and 36in. min. dimension .[310.2] {310.4}
Window wells >44in.below grade must have permanent ladder
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..[310.2.1] {310.4}
Ventilation
Natural ventilation (windows, doors, louvers)=>4% of floor area
{5% min. & 5sq.ft.}
OR .. . . . . . . . . . . . . . . . . . . . . . . . [303.1] {1203.3}
Mechanical 0.35 air changes/hr. or 15cfm per occupant.[303.1X] {1203.3}
Bathrooms 12sq.ft. {5% floor area} openable window OR .[303.3X] {1203.3}
50cfm {5 air changes/hr.} fan to outside . . . . . . [303.3X] {1203.3}
Two rooms are considered one for light & ventilation if
opening between them min. 50% of common wall AND =>10%
floor area of interior room AND at least 25sq.ft. . . .[303.2] {1203.1}
Light
In
habitable rooms, natural light
min. [8%] {10% min. & 10sq.ft.} floor area
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [303.1] {1203.2}
Bathrooms may have artificial light only . . . . . .[303.3X] {NEC 210-70a1}
So to be smart and safe, the stairs from the basement is one egress, a window is the other required.
The door out of a bedroom is one egress, the proper size window is the other.
The natural light requirements are for both rooms. Be safe, G