1.  Marriage Record:

2.  1900 Census Index/Images (online at Genealogy.com, Image #475 of 492):  102 F Street NE, Washington City, District of Columbia, Roll 162 (Book 2), p. 245A, SN 16, SD 1, ED 109, enumerated 9 Jun 1900, official enumeration date 1 Jun 1900 (extracted by Diana Gale Matthiesen):¤•

1900:  for an explanation of the column headings, please see What the Numbers in the Federal Census Mean (missing columns contained no data).

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

19

20

21

22

23

24

25

27

*

102

263

280

Straub Louis

Head

W

M

Jun 185?

43

M

10

Wash DC

Wash DC

Wash DC

Bricklayer

1

Y

Y

Y

R

H

______ Annie

Wife

W

F

Aug 1857

42

M

10

5

4

MD

MD

MD

Y

Y

Y

______ Edward

Son

W

M

Aug 1888

11

S

Wash DC

Wash DC

MD

at school

12

Y

Y

Y

______ Harry

Son

W

M

Dec 1880

19

S

Wash DC

Wash DC

MD

Printer

2

Y

Y

Y

Anderson Arthur

Son

W

M

Jul 1872

27

M

2

MD

Wash DC

MD

Day laborer

Y

Y

Y

________ Clara

D-in-law

W

F

May 1876

24

M

2

0

0

PA

PA

PA

Y

Y

Y

*F Street NE

All the children were born before our subjects married, and while only Arthur is certainly Annie's child from her prior marriage, I'm inclined to think all are.  Arthur is legally of age, but the younger boys are not, which probably explains why they are surnamed STRAUB, not ANDERSON.  It does remain possible that Edward is Louis's son, but it's very unlikely that Harry is because Louis was not married in the 1880 census.  Of course, even if Louis legally adopted the boys, the enumerator should have labeled them "step-sons" and saved us the uncertainty.

3.  WorldConnect / Ancestry World Trees (online at RootsWeb.com/Ancestry.com).