Importantly the executive order seeks modification of the "Flores Settlement" agreement which dictates that no child can be kept in detention for more than 20 days. This means that families can be detained indefinitely throughout the length of their "criminal proceeding".
Additionally, this order does not address the reunification of families that have already been separated. 
This letter has been edited to include a call for a family reunification plan and denounces the modification of the "Flores Settlement" agreement.
1. https://www.cbsnews.com/news/trump-signs-executive-order-on-family-separation-live-stream/2. https://www.vox.com/2018/6/20/17484546/executive-order-family-separation-flores-settlement-agreement-immigration3. https://www.vox.com/2018/6/20/17484300/read-trump-executive-order-family-separation-immigration-full-text
1,900+ signatures! Last edited July 16, 2018 2:47PM EST
According to the Department of Homeland Security (DHS) 1,995 minors have been separated from their guardians from April 19th to May 31st.[2,3]. Many of the people detained were asylum-seekers who entered through designated ports of entry and applied and/or sought to apply for asylum.. Once detained, children as young as a few months were separated from their guardians and parents were not informed of their children’s whereabouts. Children were taken to shelters at times erected from abandoned Walmart facilities and kept indoors sometimes five to a room meant for four.
The stress and anxiety endured by children due to the separation from their parents and/or guardians leads to great distress and trauma. The longer the separation, the greater the intensity of anxiety and depression experienced by the children. This is why we call for a family reunification plan to reunite these families as soon as possible.
Many of these families have endured considerable trauma in their home countries, trauma that led them to risk their lives and make the treacherous journey accompanied by their children- some toddlers- in search of safety.
These adverse life events negatively impacts a child’s health when they grow up as shown in the Adverse Childhood Experiences (ACEs) study. The ACE study demonstrated a replicable and dose-dependent relationship between the number of ACEs experienced- such as parental separation or divorce, emotional neglect, mother treated violently- and negative health outcomes such as ischemic heart disease, chronic obstructive pulmonary disease, liver disease, smoking, suicide attempts, poor academic achievement, alcoholism and alcohol abuse to name a few.
As healthcare professionals we believe this policy has caused direct harm to the health of our patients. Furthermore we believe that modifying the "Flores Agreement" would lead to the detention of children for longer periods of time, thus prolonging their traumatic experiences.
Therefore we call upon the President of the United States Donald J. Trump, Secretary of the Department of Homeland Security Kirstjen Nielsen, Attorney General Jeff Sessions, and the U.S Department of Justice to stop this inhumane practice. We call the aforementioned to identify and implement a family reunification plan and we ask that the "Flores Agreement" is not modified.
Resources:1. https://www.vox.com/2018/6/20/17484300/read-trump-executive-order-family-separation-immigration-full-text2.https://www.cnn.com/2018/06/15/politics/dhs-family-separation-numbers/index.html3. http://thehill.com/regulation/administration/381991-sessions-orders-zero-tolerance-policy-at-southwest-border 4. https://www.nytimes.com/2018/06/06/us/family-separations-migrants-court.html 5. https://www.nytimes.com/2018/06/14/us/family-separation-migrant-children-detention.html6. https://www.aap.org/en-us/about-the-aap/aap-press-room/Pages/StatementOpposingSeparationofChildrenandParents.aspx 7. http://www.apa.org/news/press/releases/2010/07/immigration-reform.aspx 8. https://www.cdc.gov/violenceprevention/acestudy/index.html