Apparently Polygamy is Rampant, Or Not.

All the children have the Wittman surname.
Some have death dates listed on this tree but I've not included them.
Comments after the jump.

 MICHAEL WITTMAN

 MARRIAGES
 #1: 1883 in Elk, Pennsyvania to Mary Selle (1857-1925)
 #2: 1888 in Outagamie, Wisconsin to Mary Catherine Coenen (1868-1890)
 #3: 1891 in Brown, Wisconsin to Anna Micke (1869-1940)

 CHILDREN from Marriages #1  #2  #3
 1884    Fred William               
 1885    Julia Margaret, Julia Margaret
 1887    Emelia Frances
 1888    Albert Joseph 
 1889    Monica Josephine
 1890    Anna Mary
 1892    Cecilia Christine
 1893    Michael
 1894    Norbert Henry, Norbert Henry
 1895    Mary Clara
 1896    Herman
 1898    Arthur Henry
 1899    Edward*
 1900    Genevieve Barbara, Theodore
 1903    Anton Albert
 1905    Louis*
 1907    Raymond
 1910    Clara
 1913    Regina*

*NOTE: There are three children of this marriage whose names are private on this tree. I've taken the names/dates from the 1920 US Federal Census and assuming they are the private names.

ⓑⓐⓡⓚⓘⓝⓖ  ⓤⓟ  ⓣⓗⓔ  ⓦⓡⓞⓝⓖ  ⓣⓡⓔⓔ

While bigamy is not all that uncommon, polygamy is. And even bigamy is not usually simultaneous. In most cases a spouse leaves the first family never to be heard from again and then has a second family without bothering with a divorce.
Now excluding Julia Margaret from marriage #3, marriage #2 and #3 could be correct. Wife #2 dies leaving behind the husband and child. Husband remarries and has another family. Happens all the time.
Okay, so here's a run down of the census records. The Wisconsin ones are attached to this tree, the Pennsylvania ones are not.

 Marriage #1                                                  Marriage #2 and 3
 1900            1910           1920                      1905 (WI)           1910                 1920
 Elk, PA          Elk, PA         Elk, PA                    Calumet, WI         Calumet, WI      Calumet, WI
 Michael J       Michael G     Michael                   Mick                     Mick                  Mike
 Mary F          Mary F          Mary F                    Anna                    Annie                Anna
 Frederick M   Fred W                                       Minnie (Monica)  
 Julie M                                                           Henry                   Henry
 Amiliea F       Emelia                                       Michael                 Mick
 Albert J         Albert J                                      Herman                Herman
 Annie M                                                         Edward                 Edward              Edward
 Crisselia K     Cesilea C                                   Theodore               Theodore           Theodore
 Norbet H       Norbet H       Norbet H                Anton                   Anton                 Anton
 Mary C          Mary C                                      Louis                     Louis                 Louis
 Arthur H        Arthur H       Arthur                                                Raymond           Raymond
 Jeneva B       Gemven                                                                 Clara                 Clara
                                                                                                                          Regina

The Michael Wittman in Marriage #1, according to census records, was born in Pennsylvania between 1852 and 1855. The other Michael Wittman was born about 1863 in Wisconsin. So how did two people born a decade apart in different parts of the country get confused for one another? How did children born in different parts of the country during the same time period get attached to the same father? How did Julia Margaret and Norbert Henry become part of Marriage #2? By someone mindlessly copying other people's trees that's how. Learn to think for yourself and STOP COPYING OTHER PEOPLE'S TREES!!! Ahem, I feel better now.

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