The family I believe contains our Theresa [Gaertner] Spence is as follows:
Georgii Joseph Gaertner, christened Oct 1773.
Married 21 October 1800
Maria Eva Muth, christened 10 Oct 1772.
- Maria Josepha born & christened 25 Jul 1801
- Theresia b/chr 10 Oct 1802, prob married 1823 in Baltimore, John Spence
- Joannes b/chr 24 Feb 1804
- Wallburga b/chr 24 Apr 1805
- Joannes Jorg b/chr 9 Jan 1807
- Frantz Joseph b/chr 3 Dec 1808
- Aemilianus chr. 6 Oct 1811
Her father's family:
Jorg [Georgii] Gartner, married 03 Jun 1763, Clarae Schraudolff
- Maria Eva, b/chr 29 Feb 1764, died young
- Georgius Valentinus, chr 14 Feb 1765 [maybe d. young?]
- Joannes Georgus, b. 15 Dec 1765, chr 16 Dec 1765, d. 1812
- Eva Walburgis b/chr 01 May 1771
- Jorg Joseph chr Oct 1773 married Maria Eva Muth
- Jacob b/chr 23 May 1776
- Mathaeus b/chr 31 Dec 1781
Could not locate any info on mother Clara's family.
Theresa's mother's family:
Joannes Muth married Johannae Heckler.
- Helen Thecla chr 24 Sept 1771
- Maria Eva chr 10 Oct 1772 m. Georgii Joseph Gaertner
- Anna Catharina chr 27 Sept 1774
- Laurentius chr 03 Feb 1776
- Eva Theresia chr 18 Mar 1778
- Wallburga chr 19 Aug 1779 [maybe d. young?]
- Joannes chr 28 Dec 1781
- Maria Wallburga chr 25 Mar 1783
- George William b. 1823/24
- Elizabeth Jane b. 1825/26, chr 9 May 1830*, married Wm Anderson
- Mary Catherine [same chr date* as Elizabeth - twins?]
- Francis b. 1835/36 [daughter]
- Thomas B. b. 1837/38
- John b. 1842/43
The name of their first child was another factor in eliminating the "other" Theresa's parents. It would be very common for the first child to be named after Theresa's father Georgii Gartner. Additionally, daughter Mary could be named for Theresa's mother; dau. Francis for brother Frantz; and son John for either his father John Spence or any of the Joannes Gaertners.