Most secondry sources give Maria's surname as "METSK," but there is no such surname.  On the other hand, METSCH is a very common German surname that is pronounced, "metsk."

1.  Marriage Record:

2.  Records of the Catholic Church in the town of Wiesloch [13 km S of Heidelberg] or Sankt Leon-Rot [16 km S of Heidelberg], Baden, Germany (LDS FHL Film #1052802; courtesy of Darlene Hiatt — translation tentative):

1. [??????] Wendelin – 11 Januar 1830 2. M.[Maria] Josepha – 7  [????] 1831 3. Joannes – 20 Junÿ 1833 - i Sept 1834 4. Joh. Baptist - 16 Sept 1834 5. Joannes – 29 Iuz  1836 6.  Søphia -18 Sept. 1838 - 9 Aug 1840 7. Ferdinand – 3 M a r z  1840 – 13 Marz 1841 8. Johann Philipp – 17 J??? 1842

This list suggest that "Johann (1) STRAUB, the elder" is not their son, but if not, whose son is he?

3.  Census Index:  U.S. Selected Counties, 1850 (Broderbund CD-317):  can't find.

4.  1860 Census Images (online at Ancestry.com; Image #11 of 21):  London P.O., London Twp., Monroe Co., MI, p. 390, PN 86, 676/675, enumerated 29 Jun 1860 (extracted by Diana Gale Matthiesen):¤•

John Straut	23	M		farmer	500	250	Germany
Mary    "	57	F					"
Phillip "	17	M					"

Listed two households from Paulding WISE, who is listed two households from Mary's son, Wendelin STRAUB. 

5.  1870 Census Index/Images (online at Genealogy.com, Image #13 of 26): Monroe City P.O., London Twp., Monroe Co., MI, p. 354A, PN 13, 93/94, enumerated 15 Jul 1870 (extracted by Diana Gale Matthiesen):¤•

Straub Baptiste	37	M	W	Farmer	1370	500	Baden
[Baptiste's wife and children]
______ Mary	68	F	W				Baden

Listed next to son, John STRAUB, the younger, who is listed next to son, Philip STRAUB. 

6.  1880 Census (indexed at FamilySearch.org; page image online at Ancestry.com, Image #6 of 28):  London, Monroe Co., MI, p. 453B, PN 6, SD 1, ED 181, enumerated 3 Jun 1880, official enumeration date 1 Jun 1880 (extracted by Diana Gale Matthiesen):¤•

1880:  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

8

9

10

13

21

22

23

24

25

26

58

60

Straub Wendlin

W

M

49

/

Farmer

Baden Germany

Baden

Baden

______ Clara

W

F

33

Wife

/

Keeping House

Hesse Germany

Hesse

Hesse

______ Willie

W

M

12

Son

/

at home

/

/

/

Mich

Baden

Baden

______ Mary E

W

F

78

Mother

no occupation

Baden Germany

Baden

Baden

"E"?  Is she Anna Maria Elisabetha?

7.  1890 Census:  the 1890 Census Population Schedules were destroyed.

8.  Headstone Transcriptions of Blue Bush Cemetery, London Township, Monroe County, Michigan (by Brent Havekost, transcribed by Loretta Dunham; online at the Genealogical Society of Monroe County, Michigan, web site):

Straub, Maria Anna

Sep 8, 1802

Jan 30, 1882

wife of Valentin Straub

These are obviously not straight readings of the stones, so caveat emptor.

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