JSFiddle - React, Tailwind, and code Playground

JavaScript

var objectsarray = [
  {
    name: "Mary",
    gender: "female",
    country: "USA",
    orientation: "straight",
    colorChoice: "red",
    shoeSize: 7
  },
  {
    name: "Henry",
    gender: "male",
    country: "USA",
    orientation: "straight",
    colorChoice: "red",
  },
  {
    name: "Bob",
    colorChoice: "yellow",
    shoeSize: 10
  },
  {
    name: "Jenny",
    gender: "female",
    orientation: "gay",
    colorChoice: "red",
  }
];

function getFemales(myArr){
 var i = myArr.length, ret = [];
 while (i--){
  if ('gender' in myArr[i] && myArr[i].gender === 'female') {
    ret.push(i);
  }
 }
 return ret.sort();
}

alert(getFemales(objectsarray));