Okay, so you are seeking a BIRTH CERTIFICATE and/or birth information for JESSE ROBERT HARPER (JRH). You want to establish who his parents were.
*** JESSE ROBERT HARPER was born 1911 in Iowa ***
Put a spotlight on that little chunk of text. That's what we currently know. We need all the data we can get about JRH.
* Was JRH born 21 May 1911? or...do you know his exact DOB? * Do you know where in Iowa he was born? * Do you know where he lived as a child (Tama county, Iowa?), or with whom he lived? * You have ordered his birth certificate - did you write to a county? They haven’t answered? This is absolutely the correct document to obtain - do you need help with the logistics of obtaining it?
* Did JRH die 27 May 1966? Or do you know his DOD? * Do you know where he died? * Have you ordered his death certificate? His death certificate should list his parents. * Is he buried at Golden Gate National Cemetery, San Bruno, San Mateo, California? If so, that could be a place of death.
* Do you know who JRH’s mother was? Margaret “Maggie” Butler (later Armstrong)? Marie Otto? You are implying it's one of them....How do you know this, what is your source? The obit says he was survived by his mother - does it list her name? If it lists a later married name, do you have knowledge of her maiden name (records? family lore?)? Does the obit list her residence/location?
* If you know his mother’s name, do you know when and where she married? Her date of birth, place of birth, places she lived, her parents, etc. can help us locate her marriage certificate. Her son may be the son of her husband, so info about her/her marriage is critical evidence.
* Who did JRH himself marry? * When and where did he marry? Do you know? * You say you have his marriage certificate? It should list his parents - but it does not? Did I understand that right?
* JRH’s obit refers to his step-siblings - plural. Does it give their names? Locations? Do you have other knowledge of who his siblings and step-siblings were? Their names can help us locate JRH in a census, etc., if you haven't done that already. Their birth and death and marriage certificates may list their father's name.
* Did JRH serve in the military in World War II or an earlier war?
* Do you have any census information on JRH? With whom is he living - and where?
You speculate his father was Jesse Milford Harper (JMH), born 22 August 1889 (where? and lived where?), son of John Harvey Harper and Ida Mae Shelton. You have census data etc. on him but didn't post the information - I presume you have no census that shows JRH with his father (or with his parents), or you would have posted that. : D