No where in the Bible is an angel identified as a female. The Bible does not give us much information about angelic life in heaven. It doesn’t tell us about angelic genders or even angelic names. In fact, when Jesus was talking to Nicodemus, Jesus refused to discuss heaven. John 3:12 (NLT), “if you don’t believe me when I tell you about earthly things, how can you possibly believe if I tell you about heavenly things?”
In the Bible, whenever an angel materialized, the angel would appear as a male. However, the use of a physical body was to permit communication between people and that angel. It was not to identify an angel as a male heavenly being. The human form calmed people. Were people empowered to see actual angelic bodies, they would be very fearful and perhaps unable to receive the heavenly message delivered by that angel.
Consider the story of Samson’s parents. Here are some excerpts: Judges 13:6,11,15-22, “The woman ran and told her husband, “A man of God appeared to me! He looked like one of God’s angels, terrifying to see. I didn’t ask where he was from, and he didn’t tell me his name…Manoah asked, “Are you the man who spoke to my wife the other day?” “Yes,” he replied, “I am.”…Manoah said to the angel of the LORD, “Please stay here until we can prepare a young goat for you to eat.” “I will stay,” the angel of the LORD replied “…you may prepare a burnt offering as a sacrifice to the LORD.” (Manoah didn’t realize it was the angel of the LORD.) Then Manoah asked the angel of the LORD, “What is your name?”…“Why do you ask my name?” the angel of the LORD replied. “It is too wonderful for you to understand.” Then Manoah took a young goat and a grain offering and offered it on a rock as a sacrifice to the LORD…As the flames from the altar shot up toward the sky, the angel of the LORD ascended in the fire. When Manoah and his wife saw this, they fell with their faces to the ground.… Manoah finally realized it was the angel of the LORD, and he said to his wife, “We will certainly die, for we have seen God!”
Again, when the angel told the shepherds the glad tidings of Jesus’ birth, he first had to calm them. Luke 2:9,10 (NLT), “Suddenly, an angel of the Lord appeared among them, and the radiance of the Lord’s glory surrounded them. They were terrified, but the angel reassured them. “Don’t be afraid!” he said.
In summary, the Bible does not give us information about angelic genders. However, whenever an angel delivers messages to men, that angel appears as a human male. The physical body is used to calm fears so that the person may listen to and talk to that angel without terror.